Abstract: The feral house mouse ( Mus musculus)is one of the main pest rodents in the farming area in North Xinjiang and had history of outbreak. The temporal dynamics of the hemoglobin polymorphic types in fluctuating population was analysed by means of polyacrylamide gel disc electrophoresis in different seasons. It was found that there are 6 polymorphic types and 6Hb components from 101 specimens over analysis of five periods. Their changes are very multiplicity with season(from spring to winter) and population number ( from low to high ), but the general tendency of changeis from single toward complex.The distribution of the six polymorphic types in the mice for different season is as following:two types in April, 1980 three types in June. 1980five types in August and October, 1980three types in June, 1981.Among six types, the type I and type Ⅳ are common for all seasons. The type [ is only present in mice of June and August of the high number year (1980), and it is not only appeared more early but also disappeared more quickly. It looks as if it plays a signal role for high number year. The type V and Ⅳ is only appeared in August and October when the population density is very high and disappeared when it lives through the winter.The distribution of six Hb components is not identical in every polymorphic type. There are only two components in type I; three in tgpe Ⅱ; four in type Ⅲ, Ⅳ and Ⅳ; five in type V. Among six components the A-component only exist in type Ⅳ and is the slowest for velocity in electrophoretic migartion. The F-component exist in types Ⅳ and V,is the most quickly for the velocity in migration.The I) and E arc both common components and major components for all types. They arc evidently different from other components,due to their bands are broader and the red colour is deeper before stained and darker after stained.