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.

摘要： 借鉴人类社会行为关系的规律和普适计算环境的特点，依据信任的滞后性和服务的前瞻性矛盾的动态演化规律，提出普适计算环境中信任关系的建立、信任度的衡量和更新以及基于信任的级联服务模型；通过直接和间接（第三方推荐）的方法动态地对信任程度进行多角度评估，以级联服务的方式从众多可选择的服务目标中筛选出最符合用户要求的服务，克服了单一设备不能完全满足服务请求属性和服务选择盲目性的缺点，提高服务的质量和效率。