The invention discloses an unsaturated soil 
permeability coefficient measurement device, and relates to the technical field of soil body 
permeability coefficient measurement. The device comprises a columnar straight 
pipe, a plurality of 
moisture sensors, a plurality of tensiometers, a 
soil column axial deformation measurement device, and a 
wetting front displacement 
measurement device, wherein thecolumnar straight 
pipe is used for containing a soil sample to be measured, and the upper end of the columnar straight 
pipe is provided with a loading device for applying 
axial pressure to the soil sample to be measured; the plurality of 
moisture sensors and the plurality of tensiometers are evenly arranged on the columnar straight pipe in sequence from top to bottom, water quantity changes in awater supply device and a 
water storage device are measured through a gravity measurement device; the 
soil column axial deformation measurement device measures the 
axial deformation quantity of the soil sample to be measured; and the 
wetting front displacement measurement device measures 
wetting front advancing displacement in the soil sample to be measured. By use of the device, the 
soil column axial deformation can be recorded, the change of soil column 
axial displacement is monitored to predict the deformation rule of the soil body under different 
axial force functions, so that a transientprofile method can be used, a 
wetting front advancing method can be used for measuring a soil body 
permeability coefficient, and two methods can be simultaneously utilized to accurately measure the unsaturated permeability coefficient functions of various soil bodies.