Contactless temperature measurement is an effective means to conduct mass epidemic prevention screening in response to the “COVID-19”, influenza and other infectious diseases, could avoid the risk of cross infection and realize human body temperature monitoring in public places, and can realize human body temperature monitoring in public places. In this paper, a portrait recognition and temperature measurement system are designed based on YOLOv5 and infrared camera. Infrared images are used for face target detection, and a set of forehead region assisted location algorithm relying on face and occluding objects is proposed. For portrait and glasses, masks, hats and other condition to construct the data set, as recognition of infrared image training and forecasting, implements for facial interested area (forehead) precise positioning and temperature measurement, and realize human body temperature measurement by this location, using C # development of the software interface, realize the visualization display and management of infrared image and its temperature. After the experimental test, the average accuracy of the prediction based on YOLOv5 is 94%, and the auxiliary positioning accuracy of the forehead region reaches 97. 3%. The influence of the algorithm on the infrared temperature measurement effect is within ±0. 15℃ . The system can run for a long time and has good applicability to multiple application scenarios.