Abstract: Measurement of soil evaporation using micro-lysimeter(ML) is a simple and effective method, and has great practical value in arid area of Northwest China. However, there is no uniform standard for ML design up to now. So, there is practically significance to seek ML which is applicable in such area. In this paper, some experiments for measuring evaporation using micro-lysimeters had been conducted in sandy soil and loam by MLs including different diameters, lengths, materials, sealed and unsealed. Results show that the longer the diameter of ML is, the less evaporation measured is. The difference is significant at 0.05 probability level among the evaporation values measured by ML with different diameters. The evaporation value measured with ML of 15 cm diameter is most appropriate for sandy soil, while 10 cm diameter ML is better for loam. When the diameter is shorter, the effect of length of ML on evaporation is significant, but it is not significant when the diameter is longer. ML of 20 cm length is most appropriate. The influences of the material and sealed type of ML on evaporation value are also obvious. In detail, the unsealed ML made with PVC is better for evaporation measuring in arid area of Northwest China.