Abstract: By virtue of behavior experience in human society and the characteristics of pervasive computing，in addition，according to dynamic transformation discipline between the lag of trust and the anteriority of service，a trust-based model cascade servers is put forward while trust relatiuon establishment，trust degree estimation and update are depicted.The best server satisfied with the user’s request is selected out by means of cascade servers to improve the service of quality and efficiency such as multiple evaluation to trust degree dynamically by direct and indirect methods（the third party’s recommendation），which conquers the disadvantage that a singular equipment can’t satisfy the request property and blindfold choice of service.