Taking Hami Zhengzhou ±800 kV Ultra High Voltage Direct Current (UHVDC) project as background, in order to make AC substations in the vicinity of UHVDC grounding poles avoid the harm of DC bias interference at the beginning of the design, the location of substation taking into account DC bias risk index is proposed. Considering the substation AC coupling resistance, the DC current distribution is calculated under the complex alpine soil model. The normal and over current stations are further selected. On this basis, the equipotential lines are established respectively based on the induced potential distribution of single and double UHVDC grounding electrodes. According to the economy of the power system, the nearest principle is adopted:new sites around the normal site should be built on the equipotential line; the new sites around the over-current site should be radially distributed with equipotential lines, on the basis of increasing potential difference, appropriate flow outlet site number is increased to avoid the risk of DC bias at the maximum extent. This work is supported by National Natural Science Foundation of China (No.51767023).