The failure and damage of downhole tools caused by the high temperature occur frequently in Y101 block. In order to clarify the wellbore temperature field of shale gas drilling in Y101 block, based on the thermodynamic theory, a new model of wellbore temperature field of deep shale gas horizontal well drilling that comprehensively considers the influence of mechanical and hydraulic heat source terms is established, and the influencing factors are analyzed, the main control factors affecting the bottom hole temperature are clarified, and cooling measures have been proposed. The prediction results of the new model are in good agreement with the existing model and field measurements,and the error bars within ± 5% . After considering the influence of the heat source term, the maximum annulus temperature is located near the bit, and the maximum temperature is greater than the original formation temperature,and the temperature difference increases with drilling time. The temperature difference increases linearly with the increase of drilling fluid yield, weight on bit, rotating speed and injecting temperature,and increases in a power function with the increase of drilling fluid plastic viscosity and density. When the length of the horizontal section is less than 1 000 m,the ground cooling effect is good,and when exceeds 1 000 m,the decreasing of mud density is better than that of ground cooling. After applying of mud density reduction and ground cooling, the maximum bottom hole temperature is reduced by 6 ℃ , rate of penetration is increased by 67. 51% , with remarkable effect of cooling,drilling speed and efficiency improving. The research results in this paper provide theoretical support for the bottom hole cooling in the Y101 block, and provide a strong guarantee for the efficient exploration and development for deep shale gas.