This article is pointed to the sowing theory of the vacuum type peanut sowing machine. The sowing distance of the peanut is decided by the radius of the tractor's driving wheel, the gear ratio of the chain wheel and the numbers of the peanut absorption hole. The sowing speed of the peanut may be changed by the moving speed of the tractor. The sowing distance of the peanut can not changed by the moving speed of the tractor.