If a man pray very much in all his life but at the end he goes to hell but another man all life negate the prayers but at the end he goes to heaven.Why? If we thinks that his Emman is not proper but at the same time we say that Allah raheem.

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.

Our comment on your question will be as follows:

-         Your introduction to your question is not correct. A believer who performed his obligatory prayers at their prescribed fixed times all his life –as you mentioned –and died as such, is given glad tidings of entering Paradise as the Prophet said: "There are five daily prayers that Allaah prescribed on His Slaves. Whoever fulfills them and does not miss any of them out of treating them insignificantly will have a pact with Allaah that He will let him enter Paradise.” [Abu Daawood and An-Nisaai]

Similarly, if a person abandons the prayer all his life until he died, he committed the greatest major sin after Shirk [associating partners with Allaah], and many jurists stated that such a person goes out of the fold of Islam as the Prophet said: "…whoever abandons it [the prayer], he goes out of the fold of Islam…"[At-Tirmithi] Moreover, Allaah forbade Paradise for non-Muslims, as He Says (what means): {Indeed, Allaah has cursed the disbelievers and prepared for them a Blaze. Abiding therein forever, they will not find a protector or a helper.}[Quran 33:64-65]

-         A person who used to perform the prayer all his life may enter Hellfire because of the sins which he committed, but he will not abide therein eternally. Indeed there is evidence from the Quran and the Sunnah and the consensus of the scholars that a believer may be punished because of his sins but he will not abide in Hellfire eternally, and it may be that Allaah forgives him because he used to perform the prayer regularly.

-         A person may perform the prayer all his life in this world but before he dies, he changes from righteousness and does the acts of the people of Hellfire, and consequently he enters it. The Prophet said: "A man would do the acts of the people of Paradise but he is written in the first book [i.e. the Preserved Tablet] that he is among the people of Hellfire, so at the time before his death, he would change and does the acts of the people of Hellfire, and then he dies and enters Hellfire.” [Ahmad and Ibn Hibbaan] Therefore, such a person did not do righteous deeds all his life; rather, he deteriorated and changed before his death. Another narration reads: "Indeed, a man would do the acts of the people of Hellfire for a long time and then he would end his life with [i.e. die while performing] acts of the people of Paradise." [Muslim] This person did not abandon the prayer all his life, rather he rectified himself before his death.

-         The believer should know that Allaah The Almighty does not wrong the people at all. If He punishes any of them, then this does not contradict His Mercy. Besides, if He has mercy upon any of them, then this does not contradict the fact that He is severe in penalty and the Owner of Retribution. Indeed, Allaah guides and has mercy upon whom he wills out of His Grace, and leaves astray and punishes whom He wills out of His Justice. Therefore, the questioner brother should ask Allaah for His Mercy and seek refuge in Him from His punishment, as this is better for him than these whispers which Satan throws into his heart.

-         It should be mentioned that Allaah promised His believing Slaves to reward them and not diminish anything from their acts. Allaah Says (what means): {But he who does of righteous deeds while he is a believer — he will neither fear injustice nor deprivation.}[Quran 20:112] Allaah also Says (what means): {And never would Allaah have caused you to lose your faith [i.e. your previous prayers]. Indeed Allaah is, to the people, Kind and Merciful.}[Quran 2:143] Allaah further Says (what means): {And if you obey Allaah and His Messenger, He will not deprive you from your deeds of anything, Indeed, Allaah is Forgiving and Merciful.”}[Quran 49:14]

Therefore, thanks to the Grace and Mercy of Allaah, it is not possible for a person who lived [all his life] while he is a believer and died on this to enter Hellfire eternally.

Allaah Knows best.