Due to large grain size, irregular shape and rough surface of garlic seeds, the missed sowing rate and reseeding rate are high. Aiming to mitigate these problems, a wheel-spoon type garlic seed metering device was designed, which was mainly composed of seed scoop, seed taking wheel, driving motor, bracket and seed box. The stress analyses of garlic seeds in seed taking zone, transferring zone and discharging zone of the device were carried out. The optimal structures of spoons and wheels after comparing the structural shapes of different types of spoons and wheels via discrete element simulation analyses were determined. The size of seed scoop was statistically determined. The orthogonal regression test was performed, treating the radius of seed scoop, the length of seed scoop and the rotation speed of seed wheel as test factors, and the rate of missed sowing and the qualified rate as response indexes. The regression models of missed sowing rate and qualified rate were established through analysis of the test data and then the parameters of garlic seed metering device were optimized based on the regression model. The platform test was carried out on the garlic seed metering device with radius, length and rotation speed of seed scoop as 16.30mm, 38.50mm and 10.0r/min, respectively. The results showed that the missed seeding rate was 5.50% and the qualified rate was 91.10%, which were consistent with the results predicted by the regression model. The research can provide a solid basis for precision sowing technology in garlic.