The temporal property and the grey property should be taken into account while designing security policy models; and the three aspects of security requirements of privacy，integrity，and availability of the system should be described in a policy. The Existing security policy models can not describe the temporal and the grey property,and they usually focused only on privacy or integrity. A dynamic grey temporal system (DGTS)and a grey temporal security policy specification language (GTSL) based on the dynamic semantics of DGTS are presented in this paper.