In order to improve the temperature characteristics of bandgap voltage reference, this paper took advantage of Buck's voltage transfer cell generating a positive temperature coefficient to provide a high-order curvature compensation of VBE. And Cascode structure was used to improve the power supply rejection ratio (PSRR). The circuit was simulated in 0.5 μm CMOS process. The output voltage of bandgap reference is 996.72 mV under 5 V supply available, and a temperature coefficient of 1.514 ppm/℃ can be achieved over the temperature varying from -25 to 125 ℃. The PSRR reaches 59.35 dB and an average line regulation reaches 0.4 mV/V when power supply changes from 2.5 to 5.5 V.