Requirement for playback of baseband signals of different bandwidths to the target intermediate frequency, a variable bandwidth baseband signal playback system was designed. The system took FPGA as the core data processing unit, and completed the playback function of the baseband signal by configuring the high-speed digital-to-analog conversion chip AD9122 and the clock chip AD9516. In order to solve the problem that the sampling rate of baseband signal with different bandwidth does not match the transmission rate of DAC, a multi rate processing algorithm is designed, The cascade structure of multi-stage HB filter, CIC filter and Farrow filter is adopted to realize the function of arbitrary multiple sampling rate conversion. The algorithm simulation and actual test results show that the system can play back the 1 kHz~20 MHz variable bandwidth baseband signal to the target IF with less resource consumption The playback signal has spurious free dynamic range not less than 60 dBc, meeting the requirements of the actual communication system.