Based on the lake energy budget and fake eddy diffusion equation * the lake thermal model was constructed and used in the simulation of thermal properties of Qinghai Lake, the largest saline and deep lake in China,The simulated items include the water surface temperature? tem perature profile, ice formation and thaw procedure? snow aging process etc. With the aid of the four-GCMs output about the climate condition of doubling C0₂ in this area,the potential change degree of the water thermal properties has been evaluated and discussed.