Abstract: It were investigated that the effects of pretreatment on the fast dissolubility and content of slow digestion starch(SDS)in potato flour,and determined the pretreatment methods that of main ingredients for meal powder,and analyzed the fast dissolubility,SDS content and protein nutrition of the seven matching ratio meal powders. The results showed that the solubility,expansion and SDS content of potato flour could be increased by steamed processing under normal pressure,which reached 33.79%,20.01% and 21.59%,respectively. There was no significant difference in solubility,expansion degree and SDS content between different meal powders,which were mainly made of potato flour and millet powder under normal pressure steam,but the difference in fast dissolubility was significant(P<0.05). Respectively,the solubility,expansion,SDS content and dispersity scores of the 4th meal powder were 29.9%,25.10%,24.9% and 71.88,which were better in fast dissolubility. Protein nutrition analysis of the meal powder showed that the EAA/TAA and EAA/NAA of the 4th and 5th meal powder reached 37%,37%,0.59,and 0.58,respectively,which was the closest to the ideal protein of FAO/WHO. The RCAA of the 4th meal powder was between 0.83 and 1.20,which was higher conformance with the FAO/WHO recommended essential amino acid model. The SRCAA and EAAI of the 5th meal powder were 81.02 and 72.04,respectively,and the protein nutritious was better. From which,it was objectively that the nutritional value of meal powder protein be evaluated by combining with EAA,TAA,NAA,SRCAA and EAAI. The nutritional value of the protein of the meal powder was more better,when the proportion of potato flour was 65%~70%,yellow millet was 15%~20%,black millet was 5%~10%,and apricot mushroom powder was 0.05% to 0.1%.