Accurate cement slurry temperature prediction is a prerequisite for improving cementing quality and ensuring wellbore integrity and sealing of oil and gas wells. It plays a crucial role in preventing “gas migration” and “sustained casing pressure” problems and reducing environmental pollution. The construction links before the start of cementing are neglected by the existing prediction methods, and thus, it is not reasonable to assume initial temperature conditions. In this paper, a two-dimensional transient temperature field model for cementing is developed and its reasonableness is verified. The distribution of wellbore and formation temperature fields at cementing beginning is calculated. In addition, the influence rules of several factors on the cement slurry circulation temperature are calculated and discussed. The results show that the initial temperature varies significantly and that each factor affects the fluid circulation temperature in different ways and to different degrees. If the circulating wash operation before cementing is considered, the temperature field decreases in the downhole section and increases in the uphole section compared to the assumption that the initial condition is the original formation temperature. By correcting the initial conditions, the accuracy of cement slurry circulation temperature prediction can be improved.