Abstract: Concentrating solar power（CSP） is a new way to make large-scale use of solar energy,and the heat storage system can improve the output characteristics of the CSP,and then mitigate the peak load regulation problem of thermal power units caused by grid-connected CSP.It can reduce the peak load regulation cost of thermal power units by configuring the capacity of thermal energy storage correctly.In this paper,a method for capacity configuration of thermal energy storage in CSP is presented,based on the analysis of the operation characteristics of CSP and the effect of grid-connected CSP on peak load regulation,the following factors have been taken into account such as load regulation cost of thermal power units in valley time and thermal energy storage cost.Finally,based on simulated example of IEEE 30 bus system and northwest province power grid system,the feasibility and effectiveness of the proposed method are verified.