Abstract: The vacuum interface valve is an important part of the vacuum sewage system. Based on the present situation of vacuum sewage discharge in China,a DN50 angular vacuum interface valve for outdoor sewage discharge was designed,and the flow coefficient C_v and drag coefficient K_v of the interface valve under different conditions of connection mode,body inclination angle α,spool structure were simulated and compared by Ansys CFX software. Then,the orthogonal test method was used to determine the interface valve,which was designed according to the following parameters:flow in the forward connection mode,the inclination of valve body α=45°,curved spool as the optimal structure. Finally,flow field analysis of the valve with this structure was carried out,and the internal flow was analyzed at gas-liquid ratio α_atm=3.2∶1. This research method has universality for the design and analysis of this type of interface valve and provides theoretical guidance for the design of interface valve.