Abstract: To investigate the effect of phase change microcapsules on the properties of mortar, we reported the high-performance composite phase change microcapsules using the vacuum adsorption method, where fly-ash cenosphere microporous served as a supporting skeleton and paraffin as a latent heat storage unit. The preparation phase change microcapsules were added to the mortar in equal volume sand substitution method to prepare energy storage mortars. The micro-morphology of the composite phase change microcapsules was analyzed by SEM image, and the thermal properties of the composite phase change microcapsules were characterized by DSC and TG. The influence of the introduction of the composite phase change microcapsules on the mechanical strength and temperature control performance of the mortar was studied. The test results show that the prepared composite phase change microcapsules have good dispersion ability, dense surface, and excellent cycle stability. In addition, introducing composite phase change microcapsules gives the mortar a certain temperature control performance. Compared with the blank mortar, the peak temperature of the energy storage mortar with the phase change microcapsules content of 30% decreased by 2.58℃, and the appearance time of the peak temperature was also delayed by 90 min. The mechanical strength of the energy storage mortar decreases slightly with the increase of the microcapsules content, but still meets the standard requirements. The energy storage mortar developed in this study has better mechanical properties and excellent temperature-regulating ability, and it is equally amenable to tempera-ture regulation and building energy conservation.