Abstract:Since the meridional positions of the east and west part of western Pacific subtropical high (WPSH) affect the climate over China differently, we redefined the meridional index of WPSH in this study. The mean latitude of the location of 500 hPa geopotential height maximum along several meridian in 10°-60°N, 110°-130°E and 10°-60°N, 130°-150°E is defined as new west index (Index_NEW_west) and new east index (Index_NEW_east), respectively. Their average value is defined as new meridional index of WPSH (Index_NEW). The correlation between these indices and summer precipitation over eastern China is more significant than the ridge index defined by National Climate Centre (Index_NCC), 〖JP2〗specifically for the positive correlation between Index_NEW_west and precipitation over North China Plain. The negative correlation between Index_NEW_east and precipitation over Yangtze River Basin is similar to that of Index_NCC. Regression of the 500 hPa horizontal wind with respect to Index_NEW_west (Index_NEW_east) presents anticyclonic circulation over western North Pacific and the anticyclone center locates near 38°N, 130°E (40°N, 145°E). The various collocations between north/south anomalies of Index_NEW_west/Index_NEW_east correspond to four types of rainfall patterns. The good relationship between the interannual variation of new indices and summer precipitation over eastern China could provide more valuable references for the study of precipitation prediction and interseasonal movement of rainfall band.