A ramp system is disclosed. The ramp system is configured to move a step disposed in a frame between a ramp closed position and a ramp open position along a moving direction. The ramp system may include a driving device generating driving torque and transmitting the driving torque to the step to move the step along the moving direction, a pair of guide rails extending in the moving direction at both side portions of the frame in a traverse direction perpendicular to the moving direction, a roller rotatably disposed on each guide rail to be movable along each guide rail by rotation of the roller, and a sliding frame connected to one end portion of the step in the moving direction, wherein the step is hingedly connected to the sliding frame, and the roller is rotatably connected to both sides of the sliding frame in the traverse direction.