Abstract: In order to supply a more adequate theoretical basis for the selection of afforestation plants, plant configuration and vegetation construction in Ulanbuh Region, the physiological and biochemical responses of C.roborvsky, C. stenophylla, C.davazameii and C.korshinskii to drought stress were investigated under filed condition and assessed comprehensively by means of fuzzy subordinate function method. The results showed that: the leaf water content and bound water/free water ratios of four species increased as the decreasing of soil water content. Variance analysis showed that the difference between C. stenophylla and C.davazameii was not significant but had significant difference with C. roborvsky and C.korshinskii. With the increase of soil drought, water deficit and cell membrane permeability in leaves of four species increased, however, the dehydration rate of leaves in vitro of different germplasm had the same tendency, water loss speed was rapid at 0-9 h while slow at 9-24 h. Based on the drought membership function value it was concluded that the drought resistance order of fore species was C.korshinskii>C.davazameii>C. Stenophylla>C. Roborvsky.