Abstract: As the following to previous paper, this paper studied the selection and design of pricing mechanism in electricity spot market. Firstly, this paper analyzed the applicability of three pricing mechanisms as system marginal price (SMP), locational marginal price (LMP) and zonal marginal price (ZMP), and put forward the decision-making framework of pricing mechanism, which combined theoretical analysis and market simulation. In the aspect of theoretical analysis, it sorted out the theoretical and international practice of electricity spot market pricing mechanism, giving out clearing models and price calculation methods for these three different pricing mechanisms as well as setting up compatibility re-dispatch model based on security constrained economic dispatch (SCED) model. The characteristics of three pricing mechanisms were compared and analyzed from multi dimensions, such as the function of price signal, the influence on medium and long-term market transactions, market supervision and the demands of supporting mechanism. It also discussed the cooperative relationship between pricing mechanisms and market mode along with the key issues to be considered in the design of pricing mechanism in China. In the aspect of market simulation, the IEEE 39 system was simulated based on the bi-level optimization model of three pricing mechanisms. Finally, based on the comprehensive analysis of the simulation results and the characteristics of pricing mechanisms, appropriate pricing mechanism was selected for the example system, which verified the effectiveness of the proposed decision-making framework. The two papers work together to solve the nested problems of pricing mechanism design and generators' bidding strategy.