Abstract: In light of poloidal motion velocity changed by electric drift, the paper derives the equation for safety factor when negative radial electric field existed, analyzes the influence of safety factor upon the drift displacement and motion orbit of charged particles, and established mathematical models for charged particles moving in the gradient and curvature magnetic fields. Through numerical simulation, the paper concludes new features and rules about drift displacement and motion orbits of both transit and banana particles: Negative radial electric field changes the maximum drift displacement of charged particles. When the poloidal velocity of charged particles increases, the maximum drift displaccment decrcases and contrarily it increases; Change the orbit of charged particles, the obit