Abstract: The spoon-chain type seed-metering device is widely-used in the middle and small size potato planter. Due to the polygon effect of chain transmission, the miss-seeding phenomenon of the seed-metering device is more obviously when the potato planter speed increase. The multiple seed increased when the smaller potato-seed was more than the bigger potato-seed in the seed case. Aiming at these problems, based on the speed of the machine and the size of the potato-seed as the test factors, the miss-seeding rate and the multiple seed rate as the test indexes, we set up the seed-meter test platform in the lab and made quadratic orthogonal rotary regression experiment. The experimental data were processed and optimized by software Design-Expert 8.0.6. The test result showed that optimal solution of the miss-seeding rate and the multiple seed rate was respectively 3.54% and 5.52% when the speed of the machine was 2.44 km/h and the size of the potato-seed was 41.34 mm. The research would provide field operation parameters for the spoon-chained type seed-metering device of potato planter.