Abstract: Studies were carried out in the semi-deciduous forest and the shifting cultivation land where the soil water content through plot contract experiments had continually been measured with electric resistance method for 5 years. According to the observation, the moisture dynamics of brown laterite and the hydrological effects in the tropical forests under different vegetations and human's interferences were given in this paper. The result showed that the annual water storage in 100cm soil layer is as follows: cultivated landforest land≥bush fallow, and the soil water content varied with the seasonal change of rainfall and vegetation but it-has no significant correlation with rainfall. The hydrological effect is not at all in certain increase of soil water content but mainly in water transportation and regulation.