Abstract：A dynamic audit policy model based on secure spatial DBMS was proposed. The model could fully express audit policies based on time and space constraints, and monitor users activities realtimely by using constraints mechanism. Furthermore, finegrained audit policies could be expressed by introducing coherent properties expression. Then the algorithm was presented to trigger the rules. Finally, through embedding audit policy module, constraint policy module and log module, the dynamic audit policy model based on secure spatial DBMS Sec_Vista was realized.