High penetration of wind power injections makes the three-phase power flow of the distribution network need to consider more uncertainties, and the traditional power flow methods faces severe challenges. Based on the interval analysis theory, this paper describes and analyzes the uncertainty of wind power outputs using interval numbers, and establishes a three-phase interval power flow model for distribution network considering the uncertainty of wind power injections. To solve the established three-phase interval power flow model efficiently, the method of solving the mathematical model by Krawczyk-Moore operator is proposed, based on the analysis and improvement of the traditional nonlinear interval equations, and the conservativeness of the interval results can be further reduced. The feasibility of the proposed interval power flow is verified via the modified IEEE 37-bus test system which carried out based on an established dynamic simulation experimental platform, and the simulation results show that the proposed interval power flow can better track uncertainty of wind power injections than that of the existing deterministic three-phase power flow models. It can provide a reference for the upper and lower bounds of the operating state of the system for distribution network scheduling.