Abstract: With the development of source-grid-load-storage and multi-energy complementary system, concentrating solar power plays an increasingly important role in multi-energy complementary system because of its advantages of continuity and flexibility. Accurately describing the operating characteristics of the concentrating solar power plant and obtaining the power regulation capability of the multi-energy complementary system is very important to realize optimal allocation of power resources. However, in the existing economic dispatch model, the cost of energy loss in the process of charging and discharging has not been taken into account, and there is also a lack of research on the power regulation capacity of regional power grids including concentrating solar power plants. Therefore, this paper presents a method to describe the power regulation capability of regional power grid considering the nonlinear operation characteristics of concentrating solar power plant. First, considering the nonlinear constraints of the operation process of the concentrating solar power plant and the energy loss cost of thermal storage system, a novel economic dispatching model of the power system with concentrating solar power plant is constructed. Further, in order to deal with the problem that the non-linear operation characteristics of concentrating solar power plant affect the characterization of the power regulation capacity, a linearization transformation method for the economic dispatch model of power system including concentrating solar power plants is proposed. Then, based on the multi-parameter programming theory and K-means clustering algorithm, a multi-period power regulation capability characterization method of regional power grid considering the nonlinear operation characteristics of concentrating solar power plant is proposed, in which the decoupling calculation of the feasible region of tie-line transmission power is realized and the power regulation capability of regional power grid is characterized. Finally, the IEEE-30 bus system and an actual provincial power system in China are used as examples to verify the effectiveness of the proposed method.