Abstract: There is a close relationship between the origin of the moon and the earth. Since 1880 the hypothesis of the moon from the earth fission was proposed, many hypotheses have been put forward. Popular one in recent 30 years is giant impact hypothesis, thought that a planetary body called Theia hit the proto-earth, the ejecta soon aggregate to form the earth’s satellite, the moon. Observation and theoretical study for the formation of planets are sure that earth experienced a giant impact during its late accretion, and the detection data of the moon provided the constraints on its origin, the development of the computer simulation method can trace quantitatively the impact process, get the possible ranges of reasonable in line with the constraints. In this paper, the latest three best simulated results are introduced, although different among them, in many key issues they made important progress, some common conclusions may be got, to solve the basic problem of the origin of the earth and the moon, and more researches are needed to solve the left and new problems.

Key words: the Moon, the Earth, giant impact hypothesis, simulation, earth-moon system angular momentum