Due to geological structure and other reasons, there are potential hydraulic connections between shallow and deep geothermal reservoir. Therefore, it is of great significance to recognize the phenomenon of heat and mass transfer for rational exploitation of deep and shallow geothermal. The parameters affecting the outlet temperature of production well under 50 years of operation were studied by numerical simulation using 200 m deep production well and 2 000 m deep injection well. The importance of the influence parameters was analyzed by using the composite scale sensitivity method. The results show that the higher crack width and the shorter crack length will result in a faster rise rate of outlet temperature. With the increase of fracture height, the outlet temperature of producing well increases. In the study range, the closer the recharge location is to the fracture, the lower the outlet temperature of the producing well will be at the end of 50 years. The higher recharge intensity leads to a faster temperature rise and a lower temperature at the end of 50 years. The higher recharge temperature results in the less influence of the outlet temperature, but a higher formation temperature around the recharge well. The factors influencing the outlet temperature of producing well are fracture width, recharge position, recharge intensity, water production position, recharge temperature, fracture height and fracture length in order of importance.