[Objective] The effects of drip irrigation on the distribution of fine roots of five and six years old "107" poplar clones (Populus×euramericana "Neva") in Daxing District forest farm in Beijing City was investigated in order to provide theoretical support for plantation construction under arid sandy land conditions.[Methods] Differences in fine root biomass in different directions, different horizontal distances, and different soil depths due to drip irrigation compared with conventional irrigation were determined from root samples collected by drilling.[Results] The spatial distribution pattern of fine roots was not changed by drip irrigation. Within 50 cm from the trunk (in the horizontal direction), and within the 0-40 cm soil layer (in the vertical direction), fine roots were distributed intensively. In different directions, fine roots were distributed in the following order:between plants > diagonal direction > between rows. Growth and distribution of fine roots were mainly affected by the range of the wetting zone of drip irrigation. The distribution of fine root biomass in the inter-plant direction was significantly different from the diagonal direction and the inter-row direction. The biomass of fine roots under drip irrigation was significantly different from the biomass under conventional irrigation (p<0.01).[Conclusion] There were more fine roots in poplar plantations under drip irrigation than under conventional irrigation. The increased number of fine roots can make full use of underground resources, promote the growth of trees, and improve forest land productivity.