A real-time processing system of large data volume based on FPGA is designed and implemented to address the problem of large amount of network test collection in the field of optical fiber sensing test. This paper introduces the hardware architecture and key module design of the system in detail， and focuses on the real-time processing method of large amount of data realized by FPGA through the peak-seeking module and the cross-reading and writing buffer module. The peak-seeking module is added to the FPGA to select valid data from a large amount of spectral data to reduce the amount of data transmitted， the continuity of data transmission is ensured through cross-read and write caches， and the filtered valid data are sent to the host computer. The practical application performance of the system is verified by experiments， and the results show that the system can effectively meet the data processing requirements of multi-channel optical fiber sensing demodulation based on spectrum acquisition.