Abstract:Based on the investigation of forest climate and surface runoff for 10years,the water balance of the Chinese fir forest in the three areas of the northeast low mountains,southeast loW. mountains, and the middle areas in Guangxi Zhuang Autonomous Region,was studied.The results indicate that the evapotranspiration is the greatest output in the water balance within the three areas,which increased from the northeast area to the southeast area,and then the middl area of Guangxi Region.The.infiltration water to soil layer is the second greater output,which has the opposite distribution regu lation to the evapotranspiration.The surface runoff is the least,which hasthe same doatribution regulation as the evapotranspiration.However,there is an exception to the young Chinese fir forest,in which the surface runoff is the largest,the infiltration water to soil layer is the smallest.The best ecol ogical benefit of water resources in the three areas is in the northeast Guan gxi Region.