Fourier series decomposition and synthesis experiment is the main practical course of electronicinformation specialty．Traditional experimental instruments are designed based on analog circuit technology，which have some shortcomings，such as unstable waveform，inaccurate measurement data，weak reliability and so on．This paper designs and implements a new Fourier experimental instrument based on digital frequency synthesis technology，including signal generation module，amplification module，amplitude modulation module，phase shift module and synthesis module，and optimizes the experimental scheme． In addition，the assembly efficiency and maintenance convenience are fully considered in the design of the experimental instrument．The prototype test data show that the new experimental instrument has significantly improved the signal quality and experimental data measurement of the machine．．