This paper proposes a system evaluation to calculate the number of photovoltaic(PV) modules in an aerial image to help the acceptance inspection of large-area PV module installation and PV module defects. First, the aerial image of the PV module must be converted to a grayscale image and then binarized. Extract the PV module from the background. Next, morphological erosion operations are used to remove noise and enhance the edge profile of the PV module. Multiple PV module arrays are then segmented from the image by pattern-matching. Finally, the edges of the PV modules are identified using Hough transformation. The total number of PV modules is calculated by finding the relationship between the edge number and the module number The study method determines the X-axis direction by self-defining two points in the aerial image. And use one point as the positioning origin. Calculate the coordinate information of each module. In the experiment, we rotate the image at several angles for detection. We discussed the discrepancy between the number of PV modules in the image and the number of PV modules calculated by the system.