Abstract: The data used in this paper are the monthly mean SST in the North Pacific, the monthly mean height on 500 hPa, the characteristic values of the Subtropical High at 500 hPa and the summer precipitation indices in North China from 1951 to 1986.The time-space features of the SST oscillation in the north Pacific (STONP) and the relationship between the STONP and the intensity of the summer Subtropical High, the ridge line position of the summer Subtropical High and the summer precipitation in North China are analized respectively.The influence processes of the STONP in April on the Subtropical High and the precipitation in North China in August are presented.