Abstract: The optical vision is very important for AUV(Autonomous Underwater Vehicle) to navigate, avoid obstacle and operate autonomously. This paper presents an AUV optical vision system, and presents the hardware frame and the software structure of vision system. This paper discusses the method of underwater image processing. The ANN(Artificial Neural Network) is applied to AUV optical vision. This paper presents the characteristics of objects, describes the structure and modeling of ANN. This paper presents characteristic vector of ANN and the results of recognition.