In an electronic device and method of matching an image A and an image B, grayscale centers of the image A and the image B are computed. The image A is divided into n equal parts Dk(k=1˜n) according to the grayscale center, and a grayscale density Vk of each part Dk is computed, to acquire n grayscale densities Vk(k=1˜n) which are regarded as feature data u of the image A. Feature data v of the image B is extracted in the similar way. A similarity of a grayscale density Vak selected from the feature data u and the grayscale density Vbk selected from the feature data V, is computed. Thus, n similarities are computed. A similarity β(n, u, v) of the image A and the image B is computed according to the n similarities.