Abstract: Curriculum standard of physical education and health for compulsory educaiton (2022 version) (hereinafter called The New Curriculum Standard) specifies requirements for the exercise intensity in physical education teaching in primary and secondary schools, so it is particularly important to reasonably design the exercise intensity according to the practical settings. This study aims to explore how to well design exercise intensities in physical education teaching in different thermal environments from the perspective of thermal comfort during exercise. Based on the thermal comfort model in sports, recommended value of exercise intensity were calculated in five simulation conditions by the variation of environmental temperature, relative humidity, wind speed, clothing coverage as well as human thermal comfort separately. The results show that there were differences for the reasonable exercise intensity in physical education teaching of primary and secondary schools under different thermal environments. Among them, the most influential thermal environmental factor was the ambient temperature, followed by the wind speed; while the relative humidity had the smallest impact. From the perspective of thermal comfort, the recommended exercise intensities in different thermal environments all met the criteria of The New Curriculum Standard, which proved a good perspective to design exercise intensity scientifically. The design of exercise intensity for physical education teaching in primary and secondary schools based on different thermal environments will promote pupils' sports ability, healthy behavior as well as sports morality by affecting their heat stress level, knowledge and practical ability in thermal environment as well as heat load psychological tolerance separately, which is beneficial for the formation of pupils' key competencies in physical education and health.