Abstract: In order to meet the need of partition harvest and picking of peanut, a kind of half feeding type peanut picker was designed through the investigation on the present situation of peanut production mechanization and picking methods in China.The structure and operating principle of the half feeding type peanut picker were briefly analyzed. The feeding system, transportation system and picking system of the peanut picker were mainly studied for exploring new structure and operating principle. Parameter optimization test of the test device was conducted. The relationship of picking cylinder rotate speed, clamping transmission speed and picking cylinder diameter with picking performance indexes were obtained. The results show that the optimum parameters are: 270 r/min for picking cylinder rotate speed, 11.3 m/min for clamping transmission speed and 160 mm for picking cylinder diameter. The results can provide theoretical basis and scientific guidance for designing peanut harvesting machinery in the future.