Based on precipitation data of 30 meteorological stations in the north wheat farming area from 1980 to 2004 from May to June, daily situation chart of 500hPa over Asia-Europe during the cloudy-rainy days and average geopotential height chart of 500hPa, the synoptic and climatically feature and the character of synoptic pattern of the continuous cloudy-rainy weather during the wheat harvest season in recent 25 years are analyzed. The relationship between the continuous cloudy-rainy process, the synoptic pattern and influencing system are studied. The result shows that block high with the cold vortex near the Baikal characterizes the synoptic pattern of continuous cloudy-rainy weather, in geostrophic wind filed of 500hPa, the wheat harvest area mainly locates in the boundary of south and north wind, during long cloudy-rainy days, south wind prevails in meridional wind field of 850hPa.