A discrete Boltzmann model is presented for detonation simulation. It consists of a discrete Boltzmann equation and a phenomenological reaction rate equation. In physical modeling, it is equivalent to a traditional Navier-Stokes model and a coarse grained model for thermodynamic non-equilibrium behavior. Compared with traditional fluid model, it provides more dynamic information and more kinetic information as well. The model adopts 16 discrete velocities, which has high computational efficiency. Additional degrees of freedom are introduced so that it can be used to simulate various detonations with different specific heat ratios. Several classic examples of detonation are simulated to validate the model. It shows that besides detonation dynamics where traditional hydrodynamic model works, it can also be used to study non-equilibrium effects where traditional fluid model does not work.