Radio broadcast signal monitoring is an important guarantee for the safety of broadcasting. A systematic solution to process digital signal based on FPGA platform is presented，aiming for the audio remote and local monitoring. Specially addressed in the paper includes audio signal acquisition，analysis， switching，network transmission modules and software designs. Also，the picture of actual object and test results are given. Test shows that the system is reliable and of stable performance，greatly reducing the burden of the radio listener in the broadcast station.