Abstract: A reversibly thermochromic functional cement based composite at normal temperature was prepared byadding reversibly thermochromic microencapsules in white Portland cement . The research result s show that thecolors of the composites can be changed reversibly f rom blue , green , red at lower temperature to white at highertemperature , and the switching temperature is about 42～58 ℃. Mean square analyses show that when the blue thermochromic microencapsule , B30 , is added in white Portland cement , the fineness and st rength of the composite canbe affected greatly. The water demand for the standard consistency of cement slurry increases by about 13 % , andthe flexural st rength and compressive st rength decrease by 20 %～40 % , but the setting time and the soundness ofcement are not affected. The composite has the light-absorbing and light-reflecting t ransforming function for buildings , indicating that the prepared composite can meet the demand for creation of a thermally comfortable environment of buildings.