Taking a large volume concrete raft foundation of a project in Jiangxi as an example, this study aims to explore the distribution of temperature field and stress field in the early stage of construction and the general law of variation with time by combining numerical simulation with field measurement temperature, so as to improve the condensation quality of concrete foundation. The results show that during the pouring process, the temperature of the central part of the structure rises first and then falls. With the development of concrete age, the high temperature area inside the concrete gradually shrinks, and gradually moves downward from the initial pouring center to the thickness direction. The early stress of the structure was caused by the temperature difference between inside and outside, and concentrated on the outer surface, and the temperature of the vertical center point increased faster and faster. In the first 48 h after pouring, the rapid temperature rise of concrete causes the tensile stress to exceed the allowable stress, which is concentrated on the outer surface. By arranging cooling pipes, the hydration heat of the structure can be effectively reduced, the temperature stress can be reduced, and the generation of surface temperature cracks can be effectively controlled.