This paper deals with the coverage analysis problem of elliptical orbits.An algorithm based on ergodic theory,for long-term coverage of elliptical orbits,is proposed.The differential form of the invariant measure is constructed via the perturbation on mean orbital elements resulted from the J2 term of non-spherical shape of the earth.A rigorous proof for this is then given.Different from the case of circular orbits,here the flow and its space of the dynamical system are defined on a physical space,and the real-value function is defined as the characteristic function on station mask.Therefore,the long-term coverage is reduced to a double integral via Birkhoff-Khinchin theorem.The numerical implementation indicates that the ergodic algorithm developed is available for a wide range of eccentricities.