For deep space missions, research on the energy consumption in probe s launch and transfer stages has always been a focus.This paper aims to develop a robust design method for low-energy escape orbits based on the Sun-Earth-Moon-Probe four-body nonlinear dynamics.Firstly in order to study the Earth-Moon escape manifold, the Sun-Earth-Moon-Probe four-body nonlinear dynamics is proposed.Then according to this model, two equations are established-one describing orbit s energy and the other one presenting energy s variation-which can be used to analyze the existence of low-energy escape manifold and the mechanism of energy evolution.