The conquest of Rey by Saljuqs led to the loss of power balance between Basasiri and Ibn Moslem, the Abbasid Vizier, in Baqdad.Meanwhile, the disagreement between Basasiri and King Rahim led to the weakening of Al Buya. After the domination of Saljuqs over Iran, this prepared the ground for realization of their policy of diffusing domination and their entering into Iraq as well as saying yes to invitation on the part of Abbasid caliph. To preserve his politicalmilitary situation, Basasiri grants the request by Mu’ayyid al-Din Shirazi; however, the followings result in cutting assistance to Basasiri: Fatimids’ economic problems, no trust in Basasiri, Ibn Maqrebi’s disagreement with Basasiri’s movement, and the type of view in changing the force facing Saljuqs. The head of the Shiite missioners, Mu’ayyid al-Din Shirazi, went to Cairo in secret, but the followings led to a cut between Basasiri and the head of the missioners: Basasiri’s impermanent companions, their change in position between Basasiri and Saljuqs, no loyalty towards Isma’ilite Shi’as, as well as the problems raied for Yazuri, the Fatimid vizier Mustanser. Basasiri sends gifts to caliph in Egypt and reads sermon in the name of Mustanser; however, he keeps the Abbasid caliph as his winning card in Hadithat al-Furat with his real companion in conquest of Baqdad, Quraysh bin Badran. Basasiri’s movement and proclaiming the caliphate of Fatimids was a division of political power and interests rather than a result of loyalty to Isma’ilite Shi’as.In a treaty written for Basasiri as the head of the troops, there is no mention of commitment of Isma’ilite Shi’as. Besides, identification of Imam Mahdi with Fatimid Mustanser to proclaim the association of some Imamiyya Shi’as with Basasiri reverses Ibn Athir’s report and results from the relationship between Mazid bin Sadaqa and Basasiri, rather than conformity of proclaiming a live Imam in a certain time.Thus, the views of some orientalists such as Gerhard Hoffman, T. Canard and Nuggle can be corrected and completed.