Transmission congestion management is one of the key problems to be solved in the process of establishing a spot power market in China. A reasonable congestion management mechanism is conducive to the effective allocation of system resources, the improvement of market efficiency and the maintenance of system security. First, the typical international electricity markets, i.e., PJM of US, Pool mode and BETTA mode of UK, NEM of Australia and Nord Pool are chosen to explore and describe their trade modes and congestion management mechanisms. Secondly, the actual situation of the pilot project of a spot electricity market in China is introduced. The characteristics and adaptability of different transmission congestion management mechanisms and their congestion cost allocation methods are discussed through comparison. Finally, suggestions on congestion management mechanism are proposed in order to provide some guidance for the construction of congestion management mechanism in Chinese power market in the future. This work is supported by National Key Research and Development Program of China (No. 2016YFB0901100), Science and Technology Program of State Grid Zhejiang Electric Power Co., Ltd. (No. 5211JY180015), and Fundamental Research Funds for the Central Universities (No. 2019QNA4023).