Abstract: 【Objective】To optimize chamber structure parameters of the pneumatic plate-type vegetable seed metering device, and to simplify the vacuum flow field in the air chamber as steady, regular, incompressible and turbulent fluid.【Method】The FLOTRAN module of ANSYS software was applied to simulate and analyze the air chamber with different structure parameters.【Result and conclusion】Compared to the rectangular cavity air chamber structure, the rectangular groove connected air chamber structure could save more gas flow and improve the overall strength. Pressure loss of double outlet was less than single outlet, and flow field uniformity of double outlet was better. The optimized air source location was between the fourth and the fifth suction holes calculated from both sides of the metering device. Increasing channel depth could reduce pressure loss at transition region and ensure more uniform pressure and velocity distribution. But if channel depth increased, the size of metering device would increase correspondingly, and the time for forming steady flow would be longer. According to simulation results, 4 mm channel depth was optimized. Verifying tests of the air flow field in the vacuum chamber of seed metering device show that the simulation analysis results are comparatively consistent with the actual measurement results, with a consistent pressure distribution trend. This proves the feasibility of the numerical simulation method.