By studying the prediction accuracy of the grey prediction model through the same type of buffer operator, it is found find that the predict result of the same buffer operator is very different in the same sample data sequence. For the specific prediction problem, a buffer operator is effective in this kind of problem, but ineffctive in anothers. Therefore, a new method is proposed to improve the prediction accuracy of the grey model, and the application range of the buffer operator can be expanded by using the combination method of the same type of buffer operator. Examples are given to illustrate that the proposed method is valuable.