In order to formulate  a reasonable and effective dispatching scheme of urban rail transit and realize the optimal allocation of passengers flow and vehicles times, we propose an optimal urban rail transit scheduling based on the bacteria foraging optimization (BFO) algorithm. Taking into consideration the benefits of both enterprises and passengers and with departure interval as the variable, we establish an optimal model of dispatching and analyze the process of calculation and the solution to the model using the bacteria foraging optimization algorithm. The optimal targets are the shortest waiting time of passengers  and a minimum quantity of dispatching vehicles. Stimulation experiments on the actual operation data of the No.1 rail transit in a city show that the BFO algorithm and the dispatching model can solve the problem of urban rail transit optimization effectively.