Aiming at the poor separation effect, the lower rate of tuber obvious and the high rate of tuber skindamage of the rodlink chains of small potato harvester, a poking roller shoving type potato harvester was designed, and the shoving type separate conveying device was studied. The structure and working parameters of the separate device were determined. The device adopts multistage roller to continuously push, and realizes the wave type backward separation and transportation of potatosoil. A specific cross mounting angle of the poking teeth on the adjacent poking roller, which ensures the movement track of the potato in the device, was a smooth curve. The quadratic orthogonal rotation combination experiment of three factors were carried out with the moving forward speed, the poking roller speed and hoisting height as experimental factors, the obvious rate and skindamage rate as experimental indexes. The regression equation was obtained and significance analysis was carried out by using the DPS software. The results showed that the influences on the obvious rate of the respective factors decrease in the order as below, poking roller speed, moving forward speed, and hoisting height, the influences on the skindamage rate of the respective factors decrease in the order as below, moving forward speed, poking roller speed, and hoisting height, and the moving forward speed of 1.0m/s, the poking roller speed of 60r/min and hoisting height of 150mm were the best combination factors, which leaded to the obvious rate of 99.01%, and the skindamage rate of 1.24%. The soil was broken in the process of poking tooth rotation. Potato was separated from the soil through picking and throwing of the poking tooth. Compared with the ordinary conveying device, the results show that poking roller shoving type potato harvester had good performance on improving the obvious rate, and had slightly improvement in decreasing the skindamage rate.