The invention relates to an unsaturated soil hydraulic parameter measuring device and a measuring method. The device consists of a pressure chamber 12, a pneumatic pump 21, a vacuum pump 8, a loading frame 10, an appliance base 27, hydraulic pressure pipelines 4 and 20, and pneumatic pipelines 11 and 15. The pneumatic pipelines of the pressure chamber 12 are connected with a pneumatic sensor 16, a pneumatic control valve 18 and the pneumatic pump 21; a water filling pipeline 28 of the appliance base 27 is connected with a control valve 29; the hydraulic pressure pipeline 20 in the center of the sample base is connected with a lower clay plate 14, a hydraulic sensor 9, a water volume measuring pipe 17, a hydraulic pressure control valve 19 and the pneumatic pump 21; a hydraulic pipeline 4 in the center of a top hat is connected with the an upper clay plate 14, the hydraulic sensor 9, a water volume measuring pipe 6, a hydraulic pressure control valve 7 and the vacuum pump 8; a sample 30, a top cap 13, a clay plate 14, a sample 30 and a sample base 25 are arranged between two clay plates 14 and are wrapped by rubber membranes; the sample 30, a pneumatic sensor 23, a pneumatic control valve 22 and the pneumatic pump 21 are connected with the pneumatic pipeline 11 which passes through the rubber membrane from the middle of the sample 30; and the pressure of a weight 26 is added to the sample by the loading frame 10 and a pressurizing shaft 3. The device can be used for measuring soil and water retention curve and unsaturated permeability coefficient of various soils under the condition of three-directional loading.