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Light hollow polymer microsphere （LHPM） has excellent properties such as highelasticity, good compression, ultra low density （20kg/m3） and low thermalconductivity coefficient etc., leading to their favor in fillers for heat-insulatedcoatings. However, LHPM cannot be dispersed excellently in heat-insulated paint forouter wall due to low density （25kg/m3）, resulting in poor stability of paint. In thispaper, nano TiO2/LHPM composites particles with core-shell structure was preparedby using nano TiO2,which has many excellent properties including high reflectance,covering power and strong scattering ability, to modify LHPM via vigorous stirring,..We also studied the effects of addictive, nano TiO2/LHPM composites particles andRutile titanium dioxide on film properties of heat-insulated paint for outer wall in thispaper.In our research, we optimized modification parameters of nano TiO2/LHPMcomposites particles by using activation index （H） as evaluating index. The optimalmodification parameters are that stir45min with a4500r/min speed at25℃, and themass ratio of nano TiO2/LHPM is9:1. The results of SEM, FTIR and EDScharacterizations indicate that nano TiO2/LHPM composites particles with core-shellstructure can be obtained by mechanical mixing. What is more, the mass of TiO2coating on the surface of LHPM is calculated by TG test, which is consistent with theresult of activation index （H）.The results also indicate that outer wall paint with good stability andheat-insulated performance can be obtained when amount of cellulose, which is usedas thickener, wetting agent, dispersant, and nano TiO2/LHPM composite particles are0.55wt%,0.3wt%,1.4wt%, and10wt%, respectively. The heat-insulated coating witha0.40W/（m·K） thermal conductivity and0.75g/cm3density is fabricated with500μmfilm thickness. Furthermore, the reflectivity and temperature difference of heatinsulation are87%and4℃respectively.
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