Abstract: The separation of dehydrated garlic slice is determined by human visual inspection so far. It is difficult for human to insist on strict and consistent criteria during inspection due to pungent smell of garlic. The result of human inspection is subjective and inconsistent together with low efficiency. In order to solve the problems above mentioned, a new method based on computer vision measurement was proposed to evaluate external quality of dehydrated garlic slice and a relevant device was developed subsequently. Experiment results show that the new device separates dehydrated garlic slice with accuracy of more than 80% and entrainment rate less than 32%. It is feasible for the new device based on developed method to separate dehydrated garlic slice effectively online.