One-dimensional vertical freezing experiment was carried out to study water, heat and solute transport in frozen soils. A dune sand was packed in a 35-cm acrylic column with the initial temperature of 2 ^oC and the water content of 0.15 cm³cm^-3. The TDR measurement for unfrozen water contents were preliminary calibrated with the NMR method. Eight TDR probes were horizontally inserted into the column. The boundary temperatures are kept constant: -8 ^oC at the surface and 2 ^oC at the bottom. The sand was frozen from the surface, reaching 10 cm depth at 6 h, and 16 cm at 24 h. Large amount of water moved to the upper frozen soil at the advancing freezing front due to high pressure gradient. The liquid water pressure head distribution were estimated based on the observed water content with the retention curve for the unfrozen soil, and the observed temperature with the generalized form of Clausius-Clapeyron equation (GCCE) for the water saturated frozen soil. The unsaturated hydraulic conductivity for the frozen sand was determined based on the pressure head gradient and the estimated liquid water flux from the observed water content profile. The dependency of the log-scaled conductivity on the log-scaled pressure head, d (log K)/d (log h), was found to be smaller for lower pressure heads representing the frozen soil than for higher pressure heads of the unfrozen soil. The experiment was evaluated using a modified HYDRUS-1D, which implemented the coupled water, vapor and heat movement model of Philip and de Vries, and the GCCE to describe unfrozen water characteristics. Although the simulation results reasonably agreed with the observed water contents, the freezing water characteristic curve needs to be further modified for unsaturated soils.