A vast decrement of forest area has created economical as well as ecological problem and a barrier to national development. One of solutions to this problem is to rehabilitate the forest by planting fast growing trees which will give short term benefit and hence encourage private sector investment. The purpose of the study is to analyze financial return of Eucalyptus camaldulensis plantation at the age of 4 years with 8 different growing distances at Si Sa Ket province and see if its worth investing at all distances. In addition the distance which will give the maximum return will be specified. Three indicators namely :NPV, B/C ratio at 5 discount rates i.e. : 10,11,12,13 and 14 % and IRR are used in the study. Moreover, sensitivity analysis of the project in terms of increasing cost of 10% with constant return 2) constant cost with decreasing return of 10% 3) increasing cost of 10% with decreasing return of 10% are inplemented. The financial analysis has shown that the plantation at all except for the 4x8 meter interval is worth investing. The maximum rate of return occurs at the 1x2 meter interval. For the sensitivity analysis, it is found that all the 3 cases except at the distance of 2x8 and 4x8 meter are worth investing. The maximum rate of return appears at the 1x2 meter interval.