To solve the problems of high labor intensity, low efficiency of manual picking, and lack of corresponding harvesting machinery and equipment for vegetable soybean harvesting, a spring-tooth drum type vegetable soybean picking device was designed in combination with the physical characteristics of vegetable soybean plants and the planting mode. The working principle of the spring-tooth drum picking device was expounded, the parameter design and structure optimization of the key components of the device were carried out, the kinematic of the pod was analyzed, and the factors affecting the operation effect were determined. The range of key parameters was determined and narrowed by a single factor test. Taking forward speed, drum rotation speed, and header height as test factors, and using drop rate, hanging rate, and breakage rate as experimental indicators, a three-factor and five-level second orthogonal rotation center combination test was carried out. The mathematical model between the experimental factors and the experimental indicators was established and the influence of each factor on the experimental indicators was analyzed. The model was optimized by particle swarm optimization, and the predicted optimal parameter combination was as follows: forward speed was 0.43m/s, drum rotation speed was 245r/min, header height was 4cm, and the corresponding predicted values of drop rate, hanging rate, and breakage rate were 10.6%, 4.4%, and 5.6%, respectively. The field verification test was carried out on the optimal parameter combination, and the results showed that the drop rate of the field test was 11.8%, the hanging rate was 4.0%, and the damage rate was 6.1%. The relative errors were no more than 10.1%. The variance analysis showed that there was no significant difference between the actual value and the prediction of the evaluation index. The research results can provide a reference for the further structural design and parameter optimization of the springtooth drum vegetable soybean picking device.