Abstract: A correlation analysis is made of sea surface temperature anomaly (SSTA) differences for major ocean current regions in the northwest Pacific and individual characteristic quantities for summertime subtropical high. Then a possible mechanism is discussed for the subtropical high anomaly caused by north-south difference in SSTA. By giving different SSTA distributions for the current regions in years with anomalous subtropical high and isolating key regions and optimum time intervals for the effects exerted on the high, this work offers a way of forecasting its characteristic quantities.