Abstract: The productivity and benefit of the plantations of poplar(Ⅰ-214)(Populus×euramericana ‘Ⅰ-214)') under subsurface drip irrigation(SDI) and normal irrigation(NI) at sandy soil of Beijing were studied in this paper.The results showed that the growth and yield of the plantations were increased more under SDI than NI.In 2000(4 years after planted),the average D_1.3,H and volume of trees were 21.18 cm,14.23 m and(0.181 5) m³ under SDI,which were 54.5 %、36.9 % and 247.6 % more than under NI;the productivity of the plantations under SDI reached 22.78~25.81 m³/(hm².a),which was 3.9~4.6 times more than under NI.The economic benefit of the plantation under SDI was also much greater.The profit,fund productivity rate and cost payoff rate of the plantation under SDI were 5 355 yuan(RMB)/(a·hm²),3.99 and 2.67 respectively,which were 3.43,1.70 and 2.32 times as much as under NI.Meanwhile,the ecological and social benefits of the plantation under SDI were much greater and the economic benefit increased significantly if these benefits could be converted into money.In addition,the efficiency of water using,fertilizer and energy of the plantations were more different between SDI and NI.In 1999,the used resources of water,fertilizer and electricity were 32.4 t/m³、13.5 kg/m³ and 2.8 kW·h/m³ respectively when 1 m³ timber was produced by SDI,and the corresponding data under NI were 6.1,5.8 and 6.2 times as much as under SDI.Therefore,extending the underground drip irrigation in developing the fast-growing and high-yield plantations in arid,sub-arid and seasonal arid areas is suggested according to the local economic conditions.It could not only accelerate the sustainable usage of water resources,but also highly increase the plantation yield and improve the forestry development in China.