Recently, more andmore concerns are focused on the development of the high- quality cenosphere-based thermal insulating coatings. Based upon the basic theory of the heat transfer, this paper discusses the in fluence of cenospheres'structural characteristics and loading volume on the thermal conduction of the therma l insulating coatings film, and provides themathematica lequation about the apparent coefficient of therma l conductivity which is validated in tes.t The result shows that this mathematicalmodel could give some reasonable guidelines to the formulation design of the thermal insulat ing coatings and the structural opt-im ization of the cenospheres.