In this paper，the method of estimating the retrograde orbit 1aunching energy and the to-and-fro orbits parameters by using lunar gravitation to change the orbit moving direction is discussed. The result showes that，for 1aunching a retrograde orbital sate1lite in the moon-earth p1ane，more energy is saved by using 1unar gravitation to change the orbit moving direction and than shows that by using Hohmann transfer direct1y on1y in the case，when the terminal retrograde orbita1 is higher than thirty-thousand ki1ometers. The higher the terminal orbit is，the more energy is saved. This paper a1so points out that the energy needed in lunar gravitation orbital-plane change (i.e.，the to-and-fro orbits are not in the same orbit plane) is less than that in the moon-earth plane change.