A satellite moving around the Earth is perturbed by the gravitational force of the Moon. So its orbit may not be stable. In this work, the author uses numerical method to calculate the motion of the satellite. It is assumed that the satellite is so small that it does not influence the Earth and the Moon, but itself is influenced by the Earth and the Moon. It is found that the stability of the orbit of the satellite changes as a function of the satellites distance to the Earth (or to the Moon). In three ranges of distance (which correspond to 2/1 resonance, 3/1 resonance, and 4/1 resonance...