The invention discloses a train speech amplification unit based on the ARM+FPGA architecture, which belongs to the field of embedded systems. The train speech amplification unit comprises a main control module, a codec amplification module and a communication module. The main control module comprises a main control chip and a peripheral device, and is responsible for initialization, audio storage and processing of a system and running applications, AGC and an amplitude and frequency limiting algorithm. The codec amplification module comprises a codec sub-module, a power amplifier sub-module and a detection sub-module, and is responsible for processing and amplifying audio signals of various formats and realizing the functions of current detection and audio degradation. The communication module comprises two paths of Gigabit Ethernet and RS485 and RS232 buses, and is responsible for audio and noise detecting signal transmission. The functional modules work in coordination to form a complete voice amplification unit. The train speech amplification unit based on the ARM+FPGA architecture can be used in the transportation fields of motor vehicles, urban subways, light rails and the like.