Racomitrium canescens is a bryophyte with extremely strong desiccation tolerance. The gene RcPLD from R. canescens was annotated coding a phospholipase D protein performed significant expression responses in the desiccation and rehydration processes, and supposed maybe participated in the strong desiccationtolerance function of R. canescens. In this study, the cloned coding sequence of RcPLD was used for constructing the overexpression transgenic Arabidopsis thaliana lines rcpldoe, the mechanism of the drought resistance in A. thaliana enhanced by RcPLD was preliminary analyzed by determining the drought stress tolerance and related physiological and biochemical indexes. The results showed: (1) the cloned coding sequence of RcPLD was used for constructing plant overexpression vector, the RcPLD overexpression transgenic A. thaliana lines, rcpldoe, were successfully constructed, and many T₃ generation homozygote rcpldoe lines were obtained. (2) Under normal condition, T₃ generation homozygote rcpldoe lines performed smaller size, longer vegetative period, delayed bolting, and slower aging of rosette leaves comparing with wildtype plants; under the condition of drought treatments, rcpldoe plants performed significantly better droughttolerance than the wildtype A. thaliana. (3) In the process of drought treatments, it was found the water loss rate was lowered in rcpldoe plants, damage on membrane integrity and inhibition of photosynthesis maybe decreased to a certain extent, but little was affected on the content of osmotic regulation substance. According to the research, under the condition of drought stress, water loss and photosynthesis inhibition in the rosette leaves of rcpldoe plants were decreased, then performed the drought tolerance which was stronger than the wildtype A. thaliana. This laid research foundations for further researching more functions of RcPLD and discovering more droughtresistance function related genes in R. canescens.