The invention discloses a cross-domain security access control method based on the credibility. The cross-domain security access control method based on the credibility comprises the that entity attribute information is initialized, a certificate is registered, an access request is sent, the credibility and sensitive information are verified, information is submitted and sent, information communication is conducted, and the credibility is re-checked. According to the cross-domain security access control method based on the credibility, the credibility attribute, the aging attribute, a time attenuation function and the sensitive attribute information are added based on a traditional cross-domain access control method, in this way, on one hand, the sensitive attribute is protected by comparing a credibility value with a sensitive attribute value, the final roles of a user is determined according to other attributes of the user after a role set of users is determined through the credibility values of the users, and the access right of a subject is determined according to an access control policy; on the other hand, the problem that the user behaves well at the early stage and conducts hostile attacks at the later stage can be solved, and system access security and reliability are greatly improved.