Currently, the frequent public crisis exposed the problems of government in crisis pre-warning management, and its essence reflects the crisis pre-warning lag and pre-warning dynamic deficiency. Therefore, the perfect dynamic mechanism is the key to do crisis pre-warning job well. This paper probes into dynamic mechanism and its function, analyses of the current failure of China's public crisis pre-warning mechanism, and puts forward the solutions: one is to consolidate the dynamic safeguard mechanism fully, two is to implement the dynamic control mechanism strictly, three is to accelerate and improve the dynamic feedback mechanism.