Due to the lack of coal, oil and gas, external electricity is one of the important ways for Guangxi to ensure energy supply in the future. Potential external electricity in Guangxi electricity market has different performance because of their different characteristics. Based on the characteristics and needs of Guangxi power system, this paper selects comprehensive and applicable evaluation indexes, and uses two suitable comprehensive evaluation methods which are the comprehensive score method and TOPSIS method to evaluate the competitiveness of different external electricity and alternative power supply in Guangxi electric power market. Some reasonable suggestions for external electricity absorption in Guangxi power system are put forward.