Abstract: Computer vision is a type of nondestructive detecting technique, speedy and economical. Widely acceptable in the agricultural products inspection filed, the technique has the probability to replace human vision. Appearance is a very important sensory attribute of agricultural products. It will affect the market value of agricultural products and consumers choices directly, as well as the internal quality to some extent. This article introduced the contactless layout and high lighting system components, image processing and analysis techniques of computer vision system, based on which analysis in detail its implementation in agricultural products external inspection. Focusing on the advantages and disadvantages of computer vision technology in the field, and to provide technical support for the external quality inspection of agricultural products and to ensure the safety of consumers.