Abstract: Electricity spot market trading is in full swing in China. Under the spot market bidding environment, power enterprises need to make quotations in each bidding period. This requires power enterprises to change the original cost management model, accurately grasp the real-time-cost of units participating in the bidding each period, and lay the foundation for reasonable bidding strategies. Therefore, based on the operating characteristics of thermal power generation, this paper deconstructs the real-time cost of thermal power enterprises, establishes a real-time cost calculation model and optimizes the calculation methods of each cost element, uses case analysis to verify the effectiveness of the real-time cost calculation model, and provides cost management ideas and methods for thermal power enterprises to participate in the electricity spot market quotation.