Abstract: At present, the model of studying fire cannot reflect the flow feature of smoke and gas as well as the distribution of temperature field very well. Also, it has limitation for the irregular space. The GAMBIT was used to generate the meshes for the irregular shapes of submarine cabin, and the N-S time-mean equation and k-s turbulent flow model were used to compute the flow filed. Under the assumption that the combustion chemical reaction is irreversible, fire developing process in the cabin was simulated. Through the critical fire development and the critical fire spreading time, firefighting decisions can be made. Therefore, a real-time and r eliable research method is established to provide strategies in submarine fire fighting.