I'm from Tunisia and I do pray but I have a problem that I have a beard. The problem is that we have here political problem; police catch the one who grows his beard my family tells me to cut it. Can I cut it or leave it?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Letting one's beard grow and trimming the moustache are among the confirmed commands of Sharia that all Muslims are required to obey.
It is recorded in Sahihs of al-Bukhari and Muslim and others from Ibn 'Umar (Radiya Allahu Anhu) that the Prophet (Sallallahu Alaihi wa Sallam) said: "Differ from the polytheists: let your beards grow and shave your moustache" .
According to the dominant opinion among scholars of principles of jurisprudence, it is a duty for every Muslim to let his beard grow. This opinion is based on many sound Hadith in this concern. Then, letting one's beard grow is confirmed in word and in deed of the Prophet (Sallallahu Alaihi wa Sallam). Also, all Prophets (Alaihi As-Salaam) let their beards grow. All companions of the Prophet (Sallallahu Alaihi wa Sallam) and their followers, without exception, let their beards grow.
However, The Divine Orders are based and meant for removing critical situations and warding off harm. Allah, The Exalted, Says: {Allâh burdens not a person beyond his scope. …} [2: 286]. He Says: {… But if one is forced by necessity without willful disobedience nor transgressing due limits, then there is no sin on him. Truly, Allâh is Oft-Forgiving, Most Merciful.} [2: 173].
In the same vein, the Prophet (Sallallahu Alaihi wa Sallam) said: "Shun what I have forbidden you to do, and do what I have commanded you to do as much as you can" .
Thereupon, if letting one's beard grow will give rise to some certain detrimental harm such as killing, prison, torture or displacement, and one cannot get rid of this harm except by cutting off (i.e. shortening) his heard or shaving it, then he is allowed to commit "The lesser of the two evils", i.e. he can cut off his beard. But he is not allowed to shave his beard clean unless he cannot remove the harm by simply shortening it. This ruling is based on rule of "Necessity is estimated only to the extent of its direness", which is controlled by Allah's statements in the Qur'an: {Whoever disbelieved in Allâh after his belief, except him who is forced thereto and whose heart is at rest with Faith; but such as open their breasts to disbelief, on them is wrath from Allâh, and theirs will be a great torment.} [16: 106]. He also Says: {… But if one is forced by necessity without willful disobedience nor transgressing due limits, then there is no sin on him.} [2: 173].
This means that whoever exceeds the limits stated in the above-mentioned verses, is sinful.
Basing on what we have stated above, we say it is proved by studying states of affairs of many people that most of them shave their beards without genuine reasons. They shave their beards for fear of something possibly happenings no more. Then, they base their "Necessities" on such a claim, since most of them want to escape any harm by all means, although it is natural for every true Muslim to be harmed due to being religious or adherence to al-Sunnah.
Their behavior, in fact, contradicts The Divine rules as stated in the Qur'an: {AlifLâmMîm. [These letters are one of the miracles of the Qur'ân, and none but Allâh (Alone) knows their meanings.] Do people think that they will be left alone because they say: "We believe," and will not be tested. And We indeed tested those who were before them. And Allâh will certainly make (it) known (the truth of) those who are true, and will certainly make (it) known (the falsehood of) those who are liars, (although Allâh knows all that before putting them to test).} [29: 1-3].
Again, it is normal for every righteous Muslim to face difficulties, harm and discomfort. This demonstrates one's soundness of Iman; otherwise, one should check his Iman and commitment to Islam.
In other words, as true Muslims, we have to receive every discomfort and difficulty with full and complete consent, and pray to Allah for reward in the Hereafter. This is to know that Iman requires such a "tax" and entering Paradise requires such a price.
So, if we fear every small/big harm, this leads us to turn away from Islam, step by step. So, we become alienated from Islam and its rites. Then, we come to an end that our enemies do their best to drive us to. Thus, milestones and landmarks of Islam fade away. This, for sure, will be the most dangerous consequence.
Thus, we have to be careful of the Satanic wiles.
Therefore, if one becomes sure of some unbearable harm that may befall him due to letting his beard grow, he will not be sinful - Insha Allah - in case of shaving it, but as we have stated above.
Furthermore, he should not feel at ease about such an action (shaving), rather he should yearn for the time of relief that enables him - by Allah's Favor - to comply with the commands of Allah and His Messenger (Sallallahu Alaihi wa Sallam) concerning letting his beard grow and trimming his moustache.
We pray to Allah, The Exalted, to bring Muslims back to Islam in word and in deed, to empower them and to make them follow the upright way.
Allah knows best.