Abstract: With the gradual implementation of China's renewable power consumption responsibility weighting policy, electricity sellers, as one of the main subjects of the assessment, need to consider both customer demand and renewable energy quota. The focus of the study lies in optimizing profits of electricity sellers from electricity purchases and sales by efficiently allocating electricity purchases on the basis of the fulfillment of renewable energy quota. To optimize the electricity purchase and sales strategies for electricity sellers and allocate and execute the responsibility weighting targets simultaneously, we first analyzed the electricity purchase and sales mechanism of sellers under responsibility weighting. Subsequently, we proposed the electricity purchase strategies of electricity sellers with three different contract modes and the electricity purchase strategies considering the responsibility weighting. On this basis, a monthly rolling optimization model for electricity purchase and sales was developed with the objective of maximizing the annual profit of sellers and maximizing social welfare. The results of the analysis indicate that the proposed model can facilitate sellers in conducting the assessment of the weight of consumption responsibility, enhance the systematic execution of electricity purchase and sale, and increase the profit of electricity sellers and social welfare.