Abstract:A new treatment of two time level semi Lagrangian scheme: Stable Extra polation Two Time Level Scheme (SETTLS) has been successfully applied in the dynamic frame of T213L31 and the reduced Gaussian grid is transferred to linear Gau ssian grid, which made the number of spectral truncation increase from 213 to 63 9 and formed so called T639L60 system. More than one year continuous forecast e xperiments have been done, and the results of objective verification on the perf ormance of 5 day precipitation forecasting and 10 day geo potential height fo recasting at 500hPa level are compared with the counterparts of operational system—T213L31.It shows that T639L60 system makes obvious improvement on 500hPa geo potential height forecasting over East Asia with improving one day valuable fore cast time. And it also improves the precipitation forecasting at light to heavy rain levels over all efficient times according to threat score and bias. Althoug h the threat score of T639 at storm rain level is higher than that of T213, the bias of T639 is worse than T213.