To improve the heating effect of hot air heating on asphalt pavement during hot in-place recycling (HIR), the hot-air impinging jet convective heat transfer and the heat conduction were regarded as conjugate heat-transfer process, and a theoretical model of conjugate heat-transfer for impinging jet for hot air heating asphalt pavement was established. Based on the finite volume method, the general discrete equation of conjugate heat-transfer model was presented. The temperature field distribution in the whole solution domain was obtained by using the pressure/velocity coupled semi-implicit algorithm (SIMPLE). The average heat flux and average heat-transfer coefficient were selected to reflect the heating effect on the asphalt pavement. The influence degree of hot-air outlet velocity and hot-air outlet temperature on heating effect was studied by orthogonal experiments. The simulation and experimental results show that there is a high degree of agreement between the theoretical calculation and the experiment temperature distribution, with an average error of 8.4%. Both average heat flux and average heat-transfer coefficient decrease sharply from the maximum value at the beginning of heating, and then gradually decrease to equilibrium. The simulation and the experiment of both average heat flux and average heat-transfer coefficient have the same trend, and the average errors are 6.4% and 7.8%, respectively. Both the velocity and the temperature of hot-air outlet have a significant effect on the average heat flux, while the hot-air outlet velocity has a significant effect on the average heat-transfer coefficient. However, the influence of hot-air outlet temperature on the average heat-transfer coefficient is relatively insignificant compared to the average heat flux. The research results provide a theoretical basis for temperature control and the design of hot-air heating equipment during HIR.