Abstract: The unpurified galactomannan was obtained by mechanical method. And the physical and chemical properties of galactomannan in different growth stages of Sophora japonica were studied, including the physical parameters (length, width, seed wet weight, dry weight ratio of each part), rheological properties, and contents of water-soluble and water-insoluble substances in pods. The results showed that with the continuous growth and maturity of the fruit, galactomannan accumulated in endosperm, the viscosity and water-insoluble substance of galactomannan increased gradually, while the water-soluble substance decreased gradually. With the increase of shear rate, the shear stress increased, and the apparent viscosity decreased. When the mass fraction of galactomannan gum was 0.5%, as the shear rate increased from 0 s^-1 to 85 s^-1, the viscosity of galactomannan decreased from 0.113 9 Pa·s to 0.042 Pa·s; the mass fractions of water-soluble and water-insoluble substances were 23.54% and 75.87%, respectively. With the increase of galactomannan colloid concentration, the apparent viscosity of galactomannan colloid solution increased at a certain shear rate; while with the increase of test temperature, the apparent viscosity of galactomannan colloid solution decreased gradually. In industrial production, the appropriate application conditions should be selected by comparing galactomannan with different growth periods and different physical and chemical properties.