The personality and tradition of the prophet, as messenger of Islam, have always captured the attention of scholars. Orientalists have also been concerned about this issue by maintaining different motivations. The main purposes of the Evangelical Christian Orientalists have included fighting against the true religion of Islam as well as denying the Prophet’s mission which have been always on the agenda of church leaders. They have made attempts to deny the Prophet’s mission by determining forged teachers for him and arbitrary commentary of the holy Quran. This paper aims at discussing and analyzing some reasons proposed to deny the Prophet’s mission and also based on the intra-religious evidences and valid outer-religious reasons it states that these skepticisms have been due to their incorrect presuppositions. In addition, this group of orientalists, in many cases, has distorted the historical realities and has discussed the Quran verses contrary to the commentary regulations.