Sonobuoy is used as aviation antisubmarine device to detect submarines, and its wireless communication mechanism would introduce radio interference. The speech signal needs to be identified from the submarine noise in order to facilitate sonar signal processing system to do further processing of the signal. This paper presents a TS-201 based dual-DSP sonobuoy signal processing system, and proposes an algorithm using Cubic Spline Interpolation and Pearson correlation coefficient to identify the speech signal from submarine radiated noise signal. This article describes the specific signal processing algorithm of the system, the hardware and software design of the system. This article uses a large number of data from experiments to test the hardware and software systems separately. The results of tests are analyzed, which indicate that the system function well in identifying speech signal from submarine radiated noise signal to, with a percentage of 98% correct rate.