The effect of filling the solar pond with the residual brine after desalination which is further concentrated is studied.Evaporation model of brine in different salinity is fitted through experimental results of brine evaporation,combining local meteorological conditions and using Penman-Monteith formula.Then,the consumption of residual brine after desalination and concentrating time for different salinity needed are calculated.According to the requirements of stability caused by temperature rising,a new method is proposed in which the whole filling process of solar pond can be finished through replenishing water to the pond for several times.Heat performance of the solar pond is improved by this method.