Abstract: There exists a good relationship between the longitudinal position of the subtropical high in the western Pacific and the temperature in the north China in summertime. A remarkable positive correlation region with a value more than 0.6 at the center indicates that when the subtropical high moves eastward, the temperature in north China would increase and vise versa. The anomalous longitudinal position of the subt ropical high is closely associated with the variation of the long wave pattern in the westerlies, hence influences the temperature of north China. Moreover, the pert urbation resulting from the change of the longitudinal position of the subtropical high would propagate, as a wave train, northward to the polar region then the North America thus influence the westerlies in a much wider range.