The fruit seedling separation methods of processing tomato harvesting machine are introduced, including comb method, robot picking method and vibration separation. The most popular vibration separation mechanism and eccentric vibration separation mechanism structure, working principle and characteristics are analyzed. And combining with W W type non circular gear planetary gear train motion characteristics, the method is proposed that efficient separation of processing tomato fruit seedlings can be finished by using W W type non circular gear planetary gear train to replace the existing system.