Abstract: The compressor is a key component of the integrated electricity and gas systems. The position of its operational point within the operational domain significantly impacts the safe and stable functioning of the entire system. Meanwhile, its model non-convexity significantly increases the difficulty of solving the optimal power-gas flow. A dynamic optimal power-gas flow convexification algorithm considering the operation domain is proposed based on the accurate compressor modeling and different transmission characteristics of the power and natural gas systems. First, a 3D compressor operation domain model is constructed based on the mapping relationship between the operating parameters and the state variables, and the convex envelope relaxation of the operation domain is realized through the hyperplanes. Then, a dynamic optimal power-gas flow model considering the different transmission characteristics is developed, a mixed integer second-order cone convex reformulation of the model is realized, and a convexification algorithm based on dynamic linearization and tightening convex envelope is proposed. Finally, results demonstrate the effectiveness of the proposed model, indicating that the proposed algorithm outperforms the sequential cone programming algorithm in both computational accuracy and efficiency.