For the need of daily weather prediction and an urgent call for the definition of ambient field as the initial input of regional forecasting model,the problem of truncation error in T106 dataset stored and displayed in MICAPS is discussed and indeed has been solved.The image snapshot effects of the spectra model T106 of China were also quantitatively analyzed,the ECMWF model,the JAPAN model and the KWBC Model,as well as their levels of statistic errors.