In view of existence of model systematic error, a study of biascorrection has been done to estimate and reduce systematic error. Onemoment biascorrection has been introduced in this paper. The merit of this method is that quantity of samples needed is smaller, thus estimation and biascorrection could be carried out quickly and economically. Onemoment biascorrection towards T213 global ensemble forecast of 500 hPa height, 850 hPa temperature and 2m temperature has been done. Verification towards raw forecast and biascorrected forecast shows that ensemble member homogeneity and cold bias have been improved, and ensemble mean RMSE and ACC also have been improved, especially bigger systematic error of 2m temperature forecast has been improved obviously.