Aiming at the randomness of the concrete thermal parameters measured in the laboratory and the difference of the construction site environment, a back analysis method of mass concrete thermal parameters based on the improved BP algorithm was proposed. Taking the mass concrete construction of the tunnel anchor on the south bank of the Taihong Yangtze River Bridge as an engineering example, the adiabatic temperature rise, reaction rate, thermal conductivity and surface heat dissipation coefficient were inverted. The thermal parameters were obtained by inversion analysis to predict the temperature field and guide the construction. The research results show that the uniform design method determines the thermal parameters and reduces the sample data. The BP algorithm improved by the additional momentum method can improve the learning efficiency and avoid the algorithm from falling into a local minimum.