With the development of energy storage application technology in recent years, the installed scale of energy storage has experienced an explosive growth in China's power market. The accurate quantification of commercial value of energy storage projects will help energy storage products or services to participate in the power market competition and promote the sustainable development of energy storage industry. Based on the theory of scope economy and cost benefit, a stochastic model of total factor discharging electricity price is established to describe and evaluate the commercial value of multifunctional energy storage project. Not only that, the paper analyzes the parameter attributes that affect the discharging electricity price and the constraint conditions that the power generation side, power grid side and user side energy storage projects obtain economic benefits and participate in the market competition. From this, it suggests the competition strategy and investment decision of energy storage enterprises. Based on the calculation example and learning curve, it is found that the three parameters of installation cost, system utilization efficiency and energy conversion efficiency have significant influence on the discharging price. So that enterprises can determine the appropriate business model and optimize the operation strategy according to the influence degree of different parameters on the discharging price level. Therefore, the comprehensive business value quantitative model provides clear thinking and decision-making tools for enterprise investment, market competition and policy formulation. This work is supported by National Social Science Foundation of China (No. 17BJY059).