To meet the requirements of acquisition, transport and spot efficient processing of the received signal in shallow surface frequency-domain electromagnetic detection, a digital processing system for shallow surface frequency-domain electromagnetic detection based on FPGA+DSP was proposed. Data acquisition, control, and transmission FIFO module were compiled in FPGA. New universal parallel port UPP was used to achieve high data transfer. Efficient data processing algorithm was written with orthogonal lock-in amplification method based on TMS320C6748. The system was controlled and the results were displayed with PC software through the RJ45 network port. Test results have shown that the digital processing system of the proposed architecture for different metals has a strong ability of discovery. Data transmission rate is accelerated, system working time is shortened and work efficiency is improved.