Based on equivalent medium theory，a model for nanoporous materials optical and radiative properties was proposed.Effective thermal radiation characteristic parameters were computed.Based on the non-gray anisotropically scattering Rosseland approximation，the model that can be used to quantify the level of radiation heat transfer traveling through nanoporous materials was developed.The radiation thermal conductivity of the nanoporous materials was computed.The relationships between the radiation thermal conductivity and the population volume fraction and the population diameter of nanoporous materials with different opacifiers were analyzed.The constitutive relation between the internal radiation heat transfer and multi-scale structural features and material properties of the nanoporous materials was revealed.In the future，this model should guide the design of new nanoporous materials with optimized radiative properties.