The characteristics of water absorption of soybeans were measured at five temperatures ranging from 10°C to 50°C. As for the results, two periods, i. e. the constant rate period and the falling rate period, existed in the water absorption of soybeans, and about 85% (d. b.) was the critical moisture content. When MR versus t were plotted on a semilogarithmic scale in the falling rate period, linear relations were obtained at each temperature. Using the data in the falling rate period, three parameters (B₁, K, M_e) were determined by applying a nonlinear least squares method to the approximate solution of the diffusion equation and the values of B₁ were about 1. As for the results, the measured results of the moisture content changes agreed well with the calculated results. An Arrhenius type equation was used to relate the water absorption rate constant K of soybeans to temperatures, which had a good fit to the measured data. Moreover, the volume changes of soybeans during soaking were determined utilizing measured results of the density on several moisture contents in soaking.