Aiming at the problem that traditional body size measurement methods cannot achieve remote and convenient measurement, this paper proposes a body size measurement system based on WeChat applet to be applied to remote clothing customization. The design and development of WeChat applet set specific contour acquisition contains three types The posture of the human body image data set, using the u-net network framework for training, extracting the human body contour feature map, positioning the key points of the human joints through the openpose human body pose estimation algorithm, extracting the key parts of the human body to extract the feature points, using the height ratio method and the double ellipse model The fitting body size information is fed back to the user through the WeChat applet. With manual measurement as the standard, the accuracy rate of two-dimensional size measurement in the body size measurement is 97.8%, the accuracy rate of three-dimensional size is 89.5%, and the final average total error is 3.19%. Experiment It shows that the body size measurement system based on WeChat applet can realize convenient body size measurement and remote clothing customization.