An experimental investigation was performed to clarify the heat transfer characteristics of thermal storage particle-water slurry in which micro-capsulated phase-change particles were dispersed in water through a capillary. First, the physical properties including density, thermal conductivity and specific heat of thermal storage particles were evaluated by measuring the physical properties of the slurry. From flow experiments in a capillary, it was confirmed that the thermal storage particle slurries was a power-law fluids, and the apparent viscosity of the slurries was a obtained. Next, heat transfer experiments were carried out for the slurry in the capillary. As a result, the heat transfer coefficient under the phase-change condition was found to increase up to twice the value under the non-phase-change condition. By use of appropriate properties to define the non-dimensional parameters, it was found that the heat transfer coefficients of slurry were expressed well by the empirical correlation commonly used.