A method for automatically adjusting the exposure effect of a camera comprises the following steps that S1, a statistical thread is created; S2, preview is started, whole-image data are divided into a plurality of sub-regions; S3, brightness information of each sub-region is collected; S4, according to the brightness information of each sub-region, high-brightness regions and low-brightness regions are determined; S5, according to the exposure algorithm, corresponding exposure parameters are adopted for the high-brightness regions and the low-brightness regions; S6, after exposure adjustment is carried out on the regions having different types of brightness in the whole-image data, the step S4 is repeated if the camera is not switched off, and related statistical thread resources are released if the camera is switched off. By means of the method and system for automatically adjusting the exposure effect of the camera, when photographing is carried out on an occasion where the brightness contrast is high, exposure control over the high-brightness regions in an image can be carried out so that overexposure can be prevented, exposure control over the low-brightness regions can be carried out so that underexposure can be prevented, the exposure effect can be improved effectively, detail portions of the image are kept as many as possible, and imaging quality is promoted.