Based on the CSMC 0.18μm CMOS process, a high-precision RC oscillator is designed，and the temperature compensation technology is carried out by pulse density modulation and sigma-delta modulation technology, which improves the temperature stability of the output frequency. The low-leakage switching capacitor resistor and temperature compensation resistor circuit are designed by using the frequency-locked loop architecture, and the temperature compensation of the resistance is carried out by three-point digital trimming technology. In addition, the integrator circuit uses a chopping technique to suppress the influence of offset voltage on the output frequency accuracy, and the voltage controlled oscillator uses a low temperature coefficient resistor to further improve the temperature stability. The simulation results show that the output frequency of the oscillator can be stabilized at 32MHz at different process angles, the output frequency change rate is less than 0.45% in the temperature range of -40~125°C, and the output frequency change rate is less than 0.25% in the range of 1.6~2V power supply voltage, and the power consumption of the whole system is 89.7μW. Compared with other RC oscillators of the same type，this design combines the advantages of high-frequency output, high accuracy, and low power consumption, and can be used as an on-chip clock reference.