<p>The failure of gas-bearing coal (GBC) under cyclic loading and unloading (CLU) is an instability phenomenon driven by energy. To understand the effect of gas pressure on energy behavior of coal under CLU, a series of CLU tests of coal with different gas pressures are performed using the MTS816 rock mechanics test system and a self-developed gas-sealed cans, the evolution and distribution laws of total input energy (<i>U</i>), elastic energy (<i>U</i>_<i>e</i>), and dissipated energy (<i>U</i>_<i>d</i>) are analyzed. Then, an energy-based constitutive model considering the coupled effects of gas and loading is developed and the model rationality is verified by experimental data. The results show that <i>U</i>, <i>U</i>_<i>e</i> and <i>U</i>_<i>d</i> all show a non-linear increasing trend as the stress ratio increases. <i>U</i> is mainly stored in the form of <i>U</i>_<i>e</i> and the average energy storage ratio of GBC gradually decreases with the increasing gas pressure. The root&#xa0;mean squared errors between the theoretical and experimental results are less than 0.15 and <i>R</i>-squared values are greater than 0.99, indicating good consistency between the constitutive model and experimental data. The newly proposed constitutive model can well describe the deformation behavior of GBC, providing a theoretical guidance for revealing the failure mechanism of GBC.</p>