Abstract: Using grey growing theory and differential dynamic simulation，We set up the dynamic equation of water injection developing oilfield from the time series of historic control variate and state variate. From this point, we put forward the optimum control model,and study the solution of optimum control model. We also give the approximate algorithm of dispersed optimum control model，and compute the numerical value of our country's H—L water injection developing oilfield as an example.

Key words: Water injection well, Field performance analysis, Time series analysis, Differential method, Dynamic model.