Abstract: The equilibrium configuration and magnetic distribution were achieved by numerically solving Grad-Shafranov equation in the typical long-pulse discharge (shot 33068) on EAST in this paper. Considering the motion equation of particles in magnetic field, deuterium ion orbit was simulated when negative radial electric field existed, and also, the deuterium ion capture rate was statistically calculated. The results indicate that the deuterium ion orbit converts from expansion passing particle orbit to expansion trapped particle orbit firstly, and then, to compression trapped particle orbit, and further, to compression passing particle orbit when the negative radial electric field becomes large. The deuterium ion capture rate decreases with the increase of negative radial electric field, and the smaller the initial velocity of deuterium ion, the greater the change.