Abstract: The reservoir has obviously effect on the local climate by modify the land use.In this paper,the local climate effects of reservoir in mountain area are studied by a high resolution boundary layer model.The results show that,the reservoir may increase the surface temperature in winter nearby the reservoir,with the amplitude rang from 0.4 to 0.85 ℃.The surface temperatures in spring,summer and autumn are decreased because of reservoir,the maximum value of decendent is about 2 ℃.The effect range of reservoir on the nearby temperature is small,the horizon range which the temperature variation is less than 0.1 ℃ is about 2.5 km and the vertical effect height is about 500 meter.The daily variation of temperature caused by reservoir in winter is different from other seasons.The increase of temperature in winter caused by reservoir in the daytime is greater than that in the night,but in other season,the reservoir make the surface temperature decrease in the daytime and increase in the night,the convert time is about 8 o'clock and 21 o'clock.The effect of reservoir on the relatively humidity is in the range of 3 km,with the maximum values of the increase of relatively humidity of 29.8%,37.2%,13.3% and 20.3% in winter,spring,summer and autumn respectively.The reservoir also make the nearby surface wind velocity increase,with amplitude below 0.5 m/s.