The dipole spacing can directly affects the detecting sensitivity and accuracy in the landfill leakage detection by the high voltage direct current method. Based on the high voltage DC detecting model, the impact of dipole spacing on locating leaks is analyzed taking a single leak and multiple leaks as example. The results show that the greater the dipole spacing is, the higher the detecting sensitivity is; the smaller the dipole spacing is, the higher the detecting accuracy is. For multiple leaks, only one leak can be located when the dipole spacing is greater than the distance between the two leaks. In order to detect all leaks correctly, the dipole spacing should be smaller than the distance between the two leaks.