By contrast with distilled water under the same condition, heat transfer characteristics of microencapsulated phase change material suspesion (MEPCMs) of which the phase change temperature is 50 ℃ are investigated in a micro-tube of radius of 1 mm. It appears that for Reynolds number (Re) ranging from 300 to 1000 both the average heat transfer coefficient and the average Nusselt number (Nu) of MEPCMs with different mass concentrations are higher than that of distilled water, and increase with Reynolds number increasing. Moreover, the wall temperature of the MEPCMs suspension is lower than that of the distilled water at the same Reynolds number, and it decreases as Re increases. In addition both the average heat transfer coefficient and the average Nusselt number increase as the mass concentration of MEPCMs increases, whereas the wall temperature decreases.