A new method which combines the Simplex code with the average superposition algorithm—S superposition algorithm is proposed. In the condition of the same denoising effect of the two methods, S superposition algorithm can substantially reduce the number of superposition to reduce the time of the signal processing and solve the problem broughtby the length of Simplex code. In order to verify the correctness of the S superposition algorithm, create mathematical model of the distributed optical fiber sensing system. Simulation experiment is launched with the mathematical model. The results of the simulation experiment show that the S superposition algorithm can greatly reduce the signal processing time. It proves the correctness and validity of the new method.