A bandgap voltage reference source circuit with piecewise-linear compensation is designed. It has the functions of a low temperature drift and a high power supply rejection ratio. The bandgap reference core circuit adopts the structure of three branches and cascode current mirror, which improves the rejection ratio of the power supply for circuit. According to the piecewise-linear compensation principle, the circuit adds a negative temperature coefficient current when the temperature is low. Similarly, the circuit adds a positive temperature coefficient current when the temperature is high. This kind of compensation circuit greatly improves the accuracy of output voltage for bandgap reference and it achieves the goal of reducing the temperature coefficient. In addition, the current mirror adopts the cascode structure, it not only improves the rejection ratio of power supply for circuit, but also suppresses the load effect on the mirror transistor voltage. Basing on 0.5 μm standard of CMOS technology,the circuit is simulated by Cadence Spectre software. The result shows that the temperature coefficient of reference output voltage is 2.62×10-6/℃ when the temperature ranges from -50 ℃ to +125 ℃, and the Power Supply Rejection Ratio(PSRR) reaches 88 dB when the circuit is under low frequency condition.