Aiming at the weak fault characteristics and susceptibility to external noise when a sing-phase ground occurs in the distribution network, a fault section location method based on the combination of parameter optimization optimization variational mode decomposition(VMD) and energy relative entropy is proposed. Firstly, the fault zero-sequence current is decomposed by the VMD optimized by the whale optimization algorithm, and several intrinsic mode functions(IMF) reflecting the local signal characteristics are obtained. Then, the Hilbert marginal spectrum of each IMF is obtained, the transient main frequency component of the fault zero sequence current is selected as the largest energy component, the energy difference between the adjacent detection points is represented by energy relative entroy. Through calculation and comparison, the section of maximum entropy is fault section. The simulation results show that the method is not affected by different fault conditions such as fault location, fault initial phase angle, etc, and in the presence of noise interference, high accuracy fault section location can still be achieve.