Abstract: Based on the natural similarity between the parallel computing features of cellular automataand the parallel computing architecture of the CUDA,a dam-break flood routing computing modelbased on GPU-CA is proposed.Key technologies including cellular automata(CA)model of dam-break flood routing,GPU model mapping method,calculation optimization method,and GPU/CPUcollaborative implementation for dam-break flood routing simulation and analysis are discussed in de-tail.Finally,aprototype system was developed and a case study region selected for carrying out a pre-liminary experiment.As compared to the CPU-CA model computing,the experimental results showedthat the dam-break flood routing computing based on GPU-CA model can greatly improve the computing efficiency,and also ensured the validity of the simulation results.Speedup can be improved by in-creasing the cellular grid resolution.When the cellular grid size was 10m,the speedup of model calcu-lation reached 15.9times,which can support real-time simulation analysis and risk assessment fordam-break flood routing.