Characteristics of hydrrology periods was analyzed according to the seasonal characteristics of precipitation,evaporation,dissolved snow and groundwater, and impacts of seasonal hydrological periods on soil organic matters were studied based on field investigation and laboratory analysis in the meadows of Napahai wetlands. The resulfa showed that water level fluctuated greatly in the meadows and soil organic matters were driven greatly by seasonal hydrology periods.巧namics of organic matters in 0-20cm layer appeared in an anomalous"W " shapewhile"N" shape in 20-40cm layer. The driving processes of soil organic matters in the meadows can be fitted inGauasian model.