Abstract: The choked refrigerant flow characteristics of electronic expansion valve (EEV) was analyzed. A metastability coefficient was proposed by employing the homogeneous equilibrium flow model and frozen flow model to depict the flow characteristics of EEVs, and the coefficient was applied to build a mass flow model of EEV. The modeling results were compared with the experimental data and the deviation of the predicted metastability coefficient by the model is in the range of -8.59% to 7.56%.