Solar sail spacecrafts can provide motivation rely on reflecting the sun photons, so that it is suitable for long
distance interstellar transfer task. Aiming at the problem of solar sail interstellar transfer orbit control, a new analytical control law is presented. This control law can realize the combination control of each orbit elements by setting the blending weights. The modified equinoctial orbital elements are introduced to the optimal derivation of the analytical optimal control law, and numerical simulations for the method are performed based on mercury exploration mission. Simulation results show that, the proposed control law has higher computational speed and the capability of realizing the combination control of each orbit elements, thus the solar sail interstellar transfer orbit can be obtained, which can satisfy the requirements of the project.