For the purpose to improve the cleaning performance including reducing the losses and impurity rate of peanut picker and harvester with two-stages, based on the study results on the floating velocities of different extraction components of peanut pods, the cleaning principle and scheme with double air-suction inlets combined with vibration screen was put forward. The overall structure as well as the key parts of the proposed cleaning device was designed. And the cleaning device was developed and its performance test and study was conducted under peanut harvest production condition. The parts of pneumatic cleaning named double air-suction inlets contained the front suction inlet and the rear suction which worked separately step by step and together in two steps. The front suction inlet was close to the peanut picker which cleaned lighter materials such as the peanut fruit stalk and the peanut leaf, and the rear suction inlet was close to the discharge port which cleaned immature peanut pods and the crushed stems. The tested results showed the floating velocity of different extraction components of peanut picked gained by means of type PS-20 measuring test-bed, such as peanut pods was 10.30~14.39m/s, the immature peanut pods was 7.03~8.89m/s, the crushed stems was 4.51~5.46m/s, the peanut fruit stalk was 2.80~3.35m/s, and the peanut leaf was 1.74~2.13m/s; and the optimal parameters of cleaning device of peanut picker with air double-suction combined vibration screen, three parameters, including rotating speed of crank, height of air suction inlet, and rotating speed of fan, were selected as input variables. The loss rate and the impurity rate as output parameters and the performance test for the cleaning device were conducted. A quadratic orthogonal rotary regressive experimental design was employed to develop the second order polynomial regression models, which explained the relationship between the input and output parameters, and then, the main parameters of the cleaning device were optimized through Design-Expert 8.0.6 software. Experimental results indicated that the most optimum combination was that: the crank rotating speed of 200r/min, the air suction inlet height of 135mm and the fan rotating speed of 390r/min. The loss rate of peanut pods was 1.35% and the impurity rate was 1.75%.