An orbital design method of the formation initialization based on the relative orbital element method is presented. It firstly constructed the relative motion equation of the satellite formation flying in terms of the leader and followers’ orbital elements. Then the equation was simplified when the orbit eccentricity of the leader satellite was small. And according to the satellites’ mission, a general design method for the relative trajectory was proposed. The advantage of this method is that one can get a very simple analytical formula of each follower satellite’s orbital elements when the orbital eccentricity of the leader satellite is zero. The simulation results show that the method is effective.