During early 1990s,the indices of Western Pacific Subtropical High are abnormal,e.g.,the Area Index and Strength Index of High are too high to be reliable. The possible reason is discussed,and the change of 500hPa geopotential height filed for calculating those indices should be in change of the abnormality. The National Climate Center 500hPa geopotential heights of T42 model from November 1991 to February 1996 are corrected through the NCEP/NCAR reanalysis 500hPa heights. And based on the corrected 500hPa heights,the indices for the abnormal period are recalculated.