Objective Fundus abnormalities caused by diseases can be shown in the main components of the fundus, diagnosed by clinical ophthalmologists using the equipment like ophthalmoscope, witch influenced by complex method, subjective fault and low efficiency.Hence, it is necessary to develop a computer-aided fundus image processing system as a tool to assist in the diagnosis diseases.Methods Some algorithms are proposed including the pre-processing such as contrast enhancement and spatial filtering, binaryzation, morphology, boundary extraction and skeleton extraction.Results This paper preliminary summarized the key technologies and the strategy of fundus digital image processing, an automated detection of optic cup, optic disc and blood vessel, by the simulating experiment in MATLAB.Conclusions Fully automated computer algorithms are able to detect main components of fundus images.This paper presents encouraging results in computer-aided fundus image processing system.