Based on the superlattice nanowire model, a modified model to predict the effective thermal conductivity of aerogel solid backbone is presented. We study both the size effect and interfacial resistance effect on the thermal conductivity of interconnected particles of the aerogel backbone. The effective thermal conductivity of the aerogel backbone is significantly lower than that of the pure nanowire and the single particle due to the interfacial thermal resistance. The solid thermal conductivity of the aerogel calculated by the present model is in good agreement with that by the minimum thermal conductivity model, and also agrees well with available experimental data when the aerogel density is above 100 kg/m(3). (C) 2013 Elsevier Ltd. All rights reserved.