The utility model relates to an automatic stiff aphid picking and selecting machine. The utility model belongs to the field of tobacco disease and pest control, a feeding groove is formed in the top of the left housing; an electric controller is arranged on the front side of the left housing; a feeding pushing mechanism and a feeding and discharging door mechanism are installed on the left housing, a screen drum belt wheel is installed at one end of the screen drum and connected with the front side of a supporting base installed at the top of the rack, a brush roller belt wheel is installed onthe rear side of the supporting base, and a wheel shaft of the brush roller belt wheel extends to the front side of the supporting base to be connected with a brush roller in the screen drum. According to the utility model, mummified aphid cocoon walls are prevented from being damaged; the life of the stiff aphids is influenced; mummified aphids are automatically picked and selected; according tothe method, the stiff aphids and the waste thereof are distinguished, the stiff aphid picking efficiency is greatly improved, manual operation is not needed, meanwhile, the waste generated in the picking process can be distinguished and treated in a centralized mode, waste cleaning is more convenient, the workload of workers is reduced, the time spent on putting the stiff aphids into the tobaccofield is shortened for smokers, and the biological control effect is accelerated.