In this paper , we adapt the perturbation method to derive the dispersion relation of equipartition accretion disk with self gravitation .We have also studied the instability of the aceretion disk , discussed the effects of self gravitation, magnetic field and viscosity to the instability of the accretion disk .The numerical calculation results show that the accretion disk have three oscillatical modes when we consider both self gravitation and magnetic field .One is viscous mode ,which is always stable ,the others are magneto acoustic mode and the central mode, which are usually unstable . Ou...
