Abstract: The cosmic rays in CCD (Charge Coupled Device) image are formed by high-energy particles from outer space which pass through the atmosphere, collide with particles in the atmosphere and fall on the CCD panel finally. The cosmic-ray muons are the main component of cosmic rays in the atmosphere. In order to study cosmic-ray muons' property and change rule, we need extract cosmic-ray muons in CCD images. This paper introduces an easy and effective method to extract cosmic-ray muons in CCD images. The main work includes the following steps:searching the cosmic rays candidate lists from CCD images by the Laplacian edge detection algorithm; removing bad pixels and noise from the extracted cosmic rays candidate lists; clustering cosmic rays pixels into cosmic ray events by AGglomerative NESting method; then extracting cosmic-ray muons according to the extracted features. Finally, the result of extracting cosmic-ray muons is summarized and analyzed.