Abstract: A simplified model of nonideal detonation energy release is proposed to account for the effect of nonideal detonation on underwater explosion. Based on the CJ detonation theory and the later reaction theory, the model divides chemical reactions in aluminized explosives into fast and slow reactions, and takes the released chemical energy and the slow reaction rate as the nonideal characteristic parameters. One-dimensional calculations using this model are in good agreement with the experiments, with the error in peak pressure of shock wave and the error in decay time constant less than 10% and 5%, respectively. The shock wave energies are also in agreement with the experimental results. This indicates that this simplified model has correctly described the major processes and characteristics of the nonideal detonation, and can be used in explosive design and explosion effect analysis.