In order to enhance the heat dissipation of the spindle under working condition, thermal conductivity paths were designed based on the topology optimization method. The heat conductive path was proposed to be constructed in the bearing housing and the spindle housing, which was simplified as a toroidal model. Taking the heat dissipation weakness as the optimization objective, the topological structure with the highest thermal conductivity was obtained based on the OC and IPTO algorithms. In order to analyze the influence of the heat conductive path on the circumferential heat distribution of the spindle, the thermal characteristic of the model with heat conductive paths filled with copper was investigated. Compared with the general model, the heat conductive path could reduce the temperature of the spindle from 47 °C to 33 °C when the volume proportion of the high thermal conductivity material was 40%. At the same time, the strength of the heat conductive path was analyzed, and the size of the stress was not more than 3MPa, which verified the effectiveness of the heat conductive path for efficient heat conduction.