In order to realize the mechanized planting of mini-tuber and solve the problem of large seed filling, a vibrating feeding pneumatic disc seed-metering device for mini-tuber was designed. The seed-metering device was made up of metering plate, air chamber, frame and vibrating seed feeding device. The working principle of the pneumatic disc seed-metering device was expounded. The physical properties of mini-tuber, including geometric dimension, average weight and angle of repose were researched. The structural parameters of metering plate were determined by the theoretical calculation, which contained the metering plate diameter, suction hole diameter and suction hole number. The FLUENT software was used to analyze the internal flow field of air chamber and optimize the location of pressure-outlet. The vibration frequency was calculated and verified by analyzing the movement characteristics of vibration plate. In order to verify the performance of the seed-metering device and find the best parameter combination, the orthogonal test was carried out by using the eligible index, multiple index, missing index as experimental indexes and the operating speed as experimental factor. The optimal experimental results were: the operating speed of 2.4km/h, vibration frequency of 6.5Hz, negative pressure of 6kPa, and the corresponding performance indexes were as following: the eligible index was 94.2, the missing index was 1.7 and the multiple index was 4.1, which could completely meet the requirement of technical specifications of quality evaluation in China. This study can provide references for further improving quality, optimizing the parameter for pneumatic disc seed-metering device and designing the potato planter used in farmland. The damage of mini-tuber caused by the machine was researched, and the breakage rate was under 1％ with different vibration frequencies.