Time domain reflection unsaturated permeameter and method for measuring unsaturated permeability coefficient

The invention relates to a time domain reflection unsaturated permeameter. The center of a barrel cap (11) is provided with an air outlet (1); the joint of the barrel cap (11) and a barrel wall (8) is sealed by a first rubber ring (2), and the joint of a base (10) and the barrel wall (8) is sealed by a second rubber ring (6); and 5 buried waveguides (3) are arranged at equal intervals in the barrel wall (8), a soil sample in the barrel wall (8) is isolated from the base (10) by porous stones (4), and the positions on the base, corresponding to the porous stones, are respectively provided with a water inlet (7) and a water outlet (5). The invention also provides a method for measuring the unsaturated permeability coefficient of a soil body. The method uses a time domain reflection probe to measure the water content of the soil body in the fixed positions and solves the unsaturated permeability coefficient of the measured medium by making use of the beforehand-measured soil-water characteristic curve of the mea