Abstract: Based on the conceptual model of the geothermal exploitation,a 3DEC program is used to calculate and analyze the influence of the three geothermal wells with different water injection and outlet on the temperature field of the rock mass,and geothermal wells and the water temperature of geothermal well outlet. The results show that:1)the outlet water temperature of production wells is the lowest and approximately same under a steady-state with the layout of wells presenting that the centered injection well（production well）and the peripheral production well（injection well）in numerical model;2)due to the heat superposition effect in rock mass during the process of water extraction from two adjacent production wells,the outlet water temperature increased greatly. In this situation,the outlet water temperature of production wells is the highest,and it takes the longest time to reach a steady state;3)When the water flow rate of the production well and two adjacent water injection wells doubled,the outlet water temperature will increase due to the increasing water heat transfer,and the time required to reach a steady state is the fastest;4)According to the outlet water temperature of the production wells from high to low,the optimized order of the model is 2 adjacent production wells ＞2 adjacent water injection wells ＞2 spaced production wells=2 spaced water injection wells.