In order to solve the problem of action number handing and model simplification in present time division, the associated matrix on equipment state is designed and the time is divided into several intervals based on this matrix. And then static reactive power of each time interval is optimized, the optimum solution and second best solution of each time interval are reserved. Then these solutions are used as state variables of dynamic programming to search the optimum path which has smallest time of action using dynamic programming in each time interval. At last, the solution of dynamic reactive power problem during whole scheduling period can be gotten. An example of region power system shows the effectiveness of time division and dynamic reactive power optimal method based on it.