Abstract: Binary trust-based delegation authorization mechanism is regarded as a primary method for computational resource access in open dynamic environment.An important problem is how to apply implant a more grain trust control on delegation and authorization combined with subjective trust evaluation.This problem is probed and a subjective trust evaluation is introduced instead of binary trust evaluation.A trusted role based logical system on the semantic of attribution authorization model is proposed.The concepts of trusted role and trust constraint are proposed.The trust control policies for delegation based role trust evaluation and the trust control rules for authorization based on entity trust evaluation are put forward.The computational method for entity trust degree decrease in delegation policies is built up.The policies and rules are expressed in logic syntax and the semantic of delegation authorization logic program is given.Finally,the subjective trust control on delegation and authorization is implemented in logic semantic of attribute based delegation and authorization mechanism.