Compared to conventional single-phase fluids, the latent functionally thermal fluid (LFTF), with phase change particles of μm magnitude in size dispersed in it, shows much greater apparent specific heat and heat transfer rate between the fluid and the duct wall. Therefore, for given heat transportation quantity, the mass flow rate and the pump consumption can be reduced greatly. Due to these, LFTF is a promising material in the fields of heat exchanging. In this paper, phase change material (n-tetradecane) was encapsulated by polymethyl mathacrylate (PMMA), polystyrene (PS) and blend of them by internal phase separation method to form microcapsule of 1~2μm in size. The chemical structures were demonstrated by using Fourier transform infrared spectroscopy (FTIR). The core-shell structure was observed using phase contrast microscope. Differential scanning calometry (DSC) results indicated that the phase change enthalpy of the containing 75wt% n-tetradecane as core material reaches 150.7 J/g.