Abstract: In monsoon area,if solar radiation,precipitation,geography environments(including topography and elevation) in a drainage basin are the same as that of another drainage basin,respectively,the climate condions in the two basins are alike,and the evaporation of both of lake and land surface of the two basins are also alike,respectively.The mufti-approching method which is based on these facts is used to determine the climate parameters of the J.E.kutzbach's hydrolic and energy balances,such as fractional cloud cover,surface albedo,surface temperature and surface water vapor pressure,and to calculate paleoevaporation and paleoprecipitation of drainage basin.This method is used to model the combined hydrological and energy and balances of Paleolake Qinghai,and yields an estimate of 585土lOmm for annual precipitation during Holocene Megathermal,which is at least more 200mm/a than the current rainfall in Qinghai Lake basin.