The shortcomings of the reliability analysis are pointed out by investigating the current situation of reliability analysis of subsea tree at home and abroad. Several typical risk assessment methods are introduced and the applicability of the methods to the shallow-water subsea tree is analyzed. Aimed at Bohai shallow-water subsea tree system, the fault tree analysis model is established, and the importance ranking of the key structure is obtained. According to the analysis result and combined with the actual characteristics of the oil and gas fields in Bohai Sea, some practical engineering suggestions on the design of tubing hanger, subsea tree protection device and production valve group are put forward, to provide the theoretical basis for forming a set of underwater subsea tree risk assessment and reliability analysis system suitable for shallow-water oil and gas fields and also provide important reference for the independent research and development, optimized design and safe operation of the subsea tree in shallow-water in China.