The utility model discloses a circuit system of a signal generator. The circuit system comprises a control chip U1, a control chip U2, a frequency band regulating circuit, a frequency regulating circuit and an amplitude regulating circuit, wherein the control chip U1 is connected with each of a duty ratio regulating circuit, a waveform selection circuit, the frequency band regulating circuit, the frequency regulating circuit, a power supply and the amplitude regulating circuit; the amplitude regulating circuit is connected with the control chip U2; the control chip U2 is connected with the power supply, an amplitude value attenuator circuit and a signal output end respectively. According to the circuit system of the signal generator, a chip ICL8038 is taken as a kernel component, square wave, triangular wave and sinusoidal wave can be output, the frequency regulating range is large, the wave form distortion is small, the practicability is high, the circuit structure is simple, the cost is lower, and the circuit system of the signal generator is very suitable for being popularized and applied.