A novel precise 6DOF Planar magnetic Levitation platform has been introduced in this paper, which is suspended through three sets of Levitation coil. To aim directly at the Levitation system of the planar magnetic Levitation stage which is a nonlinear and strong coupling system, a modified secondorder autodisturbance rejection controller (ADRC) is proposed. This controller not only observes and compensates the inner disturbance and outside disturbance, but also overcomes the rough character of nonlinear function in nonlinear state error feedback of conventional ADRC. The result of simulation and experiment indicate the Levitation altitude control system of the Planar Magnetic Levitation Stage has better robustness, dynamic and static performance by using modified secondorder autodisturbance rejection control scheme.