Eucalyptus planting area is larger and contiguous distribution in Danzhou Forest Farm, lying in the west of Hainan, China. 4 years old eucalyptus forest and artificial coconut grove, the space adjacent and the natural conditions similar, were selected as comparative research plots. Study on the soil moisture environment differences of eucalyptus plantation and artificial coconut grove by continuous field-point sampling. The results show that: 1) The soil surface, subsurface and deep average soil moisture content are 6.66%, 9.71% and 9.67% of eucalyptus forests plots, and which are 7.19%, 10.04% and 11.31% of coconut grove plots. 2) The average soil moisture contents of eucalyptus forest plots are respectively 0.84%, 0.67% and 1.02% less than coconut grove plots in the whole, dry and wet seasons. 3) The annual range of variation of eucalyptus plantation's soil moisture is 3.77%, and that of artificial coconut grove is 3.18%. In similar natural conditions, eucalyptus forests' average soil moisture contents are less than coconut grove. The soil moister difference between the two plots is 0.57% in wet season, and 1.16% in dry season. Which mean that eucalyptus plantation consumes more soil moisture than artificial coconut grove, and eucalyptus planting may have a negative ecological impact on soil moisture environment? [ABSTRACT FROM PUBLISHER]