Abstract:A study on comparison of five methods for the transpiration water-comsumption conducted in poplar plantation in Shandong province(Populus deltoides CV．“Lux”ex．I -69/55)and Ningxia Autonomous Region(Populus opera)from 1989 to 1991．The five measuring methods are whole-tree potometer，quick-weighing method，LI-1600 porometer，heat pulse technique and Penman—Monteith method．The results of the study are as follows：(1)Supposing that the relative value of daily transpiration waterconsumption per tree measured with whole-tree potometer is 100%，the relative value measured by quick-weighing method is 130％-140％，the relative value measured with LI-1600 porometer is 291% and the relative value measured by heat pulse technique is 90.14％．(2)Supposing that the relative value of the daily transpiration water-consumption per tree measured by heat pulse technique is 100%,the relative value measured by quick-weighing method is 88％in 6-year-old tree and 112％in 2-year-old tree．(3)The value measured with LI-1600 porometer is 30％-90％higher than that measured by quick-weighing method in Ningxia arid zone and 140％-220％higher than that in more humid area of Shandong Province．(4)The value measured by Penman-Monteith method is very close to that measured with whole—tree potometer and that measured by heat pulse technique with errors less than 2％．