Is it allow marrying a very poor person, but he is an Imaam in the mosque and very religious and very kind. I'm very high level than him, is it good for me or bad?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

If the person who proposes to marry you is a religious man and has a good moral character as you mentioned then you should accept him as a husband, as the Prophet said: "If a man whose religion and moral character are pleasing proposes to marry your daughter, then marry her off to him, otherwise there will be great mischief and corruption on earth." [At-Tirmithi] Indeed religion and good moral character are the criteria for accepting or refusing someone who proposes for marriage. The fact that he is poor is not a criterion for refusal, and Allaah may make him rich. Allaah Says when speaking about marrying the unmarried (which means): {If they should be poor, Allaah will enrich them from His bounty.}[Quran 24:32]. The fact that you are of a higher social status does not constitute an obstacle according to the correct opinion of scholars. Indeed Allaah Says (which means): {Indeed, the most noble of you in the sight of Allaah is the most righteous of you.}[Quran 49:13]. Moreover, it is confirmed that the Prophet said: "Indeed Allaah has purified you from the pride of the pre-Islamic era, and purified you from boasting about your family lineage. People are either a pious believer or a dissolute person. All of you came from Aadam and Aadam was created from clay, [so it is not befitting for someone who originally came from clay to be proud of himself]; I swear by Allaah, you should abandon boasting about your family lineage who are the coal of Hellfire, otherwise you will be as debased and disgraced in the Sight of Allaah as the dung beetle which pushes rotten things with its nose." [Ahmad and Abu Daawood]

It is confirmed that Bilaal married Haalah Bint 'Awf, the sister of 'Abdur-Rahmaan Ibn 'Awf ; she was from the tribe of Quraysh whereas he was from Ethiopia. So the most important thing to take into consideration when marrying is religion.

Therefore, if you want to marry this man, you should not take your status as a criterion in consideration and you should refrain from thinking that you are from a higher social status than him, so that your marital life will be set in the best and right way. 

Allaah Knows best.