Abstract: Along with the further deepen reform of electricity market and the sustained and fast development of renewable energy in China, it is an inevitable trend for renewable energy to participate in electricity spot market and it is a flexible way for the accommodation of renewable energy. Here, the current development situation of renewable energy in China was reviewed, and from both aspects of market mechanism and power grid operation security the key problems of renewable energy participating in electricity spot market were discussed and analyzed, and it was proposed that in the aspect of market mechanism the necessity of renewable energy participating in electricity spot market could be determined by market fairness testing and market competitiveness testing. In the aspect power grid secure operation, the feasibility of renewable energy participating in electricity spot market could be determined by the analysis on energy balance, power balance, and peak-load regulation ability system ramping capability and climbing ability. By means of the case analysis on renewable energy in a certain region participating in electricity spot market, it was put forward that an auxiliary service market for deep peak-load regulation should be constructed to stimulate thermal generating units participating in deep peak-load regulation through the market to provide sufficient and flexible regulating ability to ensure both accommodation of renewable energy and secure operation of power grid.