The thermal conductivity models of polymer-based carbon nanotube-filled composites were reviewed, and the mechanism of carbon nanotubes (CNTs) filled in composite thermal conduction systems were analyzed. The homogeneous, heterogeneous, random dispersion models as well as the calculation methods commonly used in heat conduction were summarized. The models enrich the thermal conductivity theory and can make preliminary predictions of the thermal conductivity of composite materials, but there are approximate or simplified treatments in terms of numerical values. The prediction of carbon nanotube composite materials cannot be used widely. To improve the accuracy of prediction, more attention should be paid on the thermal resistance at the molecular interface.