At present, spherical concave?convex combination structure is widely used in the plate of pressure-filtered water electrolyzer. The purpose is to enhance the disturbance degree of flow and make the distribution of electrolyte more uniform. In order to further improve the flow field distribution, five different concave?convex combination structures were combined with the electrolytic cell plate structure. The flow characteristics and flow field distribution characteristics in different concave?convex combination structures were analyzed and compared by numerical simulation method. The results showed that there were negative velocity distribution regions in the velocity component uz of the five structure channels, which was dominated by circulation flow, and the turbulent kinetic energy was also larger in this region, among which case C and case E structure were most obvious. The local vortices showed the vortices moved from the edge of the depression structure to the interior of the depression, and the details of the vortices flow were closely related to the the concave?convex structure. The distribution of the mean vorticity flux and the vorticity value showed that the concave?convex structure mainly affected the local vorticity intensity, but had little influence on the overall flow, and the local vorticity value in case B was the largest. The uniformity of the flow field distribution was related to the shape and size of the windward face of the concave?convex structure, among which case D teardrop structure had the best uniformity of flow field distribution and case C ellipsoid structure was the worst.