Abstract: The forecasting model of GM(1,1)is one of the core content of the grey system theory.In this paper we utilize the method of"the least square estimate"to find the constant number c in the time response sequence of whiterization equation of GM(1,1),then create the optimum time vesponse sequence of whiterization equation for GM(1,1).By contrasting the optimum one to the GM(1,1)about the simulation and prediction,we can conclude that the optimum one is superior in prediction and simulation.

Key words: GM(1,1), time response sequence, the least square estimate