Many organizations use PKI (public key infrastructures) to support internal business processes, but most organizations have industrial partnerships with other organizations, and these alliances can exploit B2B e-commerce capabilities by connecting corporate PKI. After we have realized the information exchange, authentication safely between different PKI networks with the help of computer technology up to date, especially we focus on access control policy research. An improved role hierarchy model is proposed which has integrated the temporal RBAC with X.509v4 PMI (Privilege Management Infrastructure). The temporal permission assignment algorithm is given as a key technique. The access control policy improves the security of the system no matter the access coming from inside PKI networks or outside PKI networks.