给出了沿椭圆轨道运动航天器真近点角和偏近点角的运动方程。用迭代法求出偏近点角变化规律，讨论了迭代收敛的充分条件。用数值积分方法求出真近点角与时间的关系曲线。数值模拟结果表明，该文提出的迭代计算方法有效且精度高，可作为航天器轨道计算的一种方法。The analytic formulations are presented of the epicyclic motion of a spacecraft about the true anomaly and the eccentric anomaly. The eccentric anomaly as a function of time is calculated by the iterative method. And the iteration’s convergence-condition is discussed. The relationship between the true anomaly and the time is gotten by the numerical integral method. The numerical simulation’s results of this approach are presented.