Signal-generator is a kind of signal source in common use, broadly applied at the electronics electric circuit, auto control system and teaching experiment etc. The system is based on single chip AT89S52 control signal generator, variety wave-form, the period of wave can be controlled by procedure, at outer circle spare part of the machine, plus independence type keyboard , which can control wave increase or decrease of form-frequency and the choice of wave-form, at the same time LED display frequency size. In this paper, the development status of signal generator in abroad and our country is told, and discusses the plan of the signal generator based on the controlling of AT89S52, also introduces and compares several kinds of waveform plan of signal generator, Importantly talks about the plan of the signal generator which is based on the AT89S52’s controlling, including schematic diagram, pictures of Functional modules, hardware circuit diagram, proposes plan to sovle anti-interference design for the difficulties in designing. In the design of system’s overall scheme, I divide the signal generator into five modules: keyboard module, SCM module, signal generating module, analog signals adjusting module, display module, and design the software and hardware according to every modules, detailed think about and design the specific circuit. In the end, this paper carries out to test system’s functionality basing on the signal generator’s main functionality, also explains the result basing on the waveform and data.