An oxygen compensation algorithm and calibration strategy are proposed to address the problem that the zirconia-based NOx sensor signal is affected by the oxygen content of vehicle exhaust, which may result in poor accuracy. A simulation test is conducted according to the working principle of the NOx sensor, the relationship between pump current IP2 and NOx concentration at different oxygen content is analyzed. The oxygen compensation algorithm is derived, and the relationship between oxygen content and compensation coefficient is analyzed. A real-time compensation scheme for IP2 error is designed. Consequently, the error of IP2 in the range of oxygen content from 0% ~ 20% and NOx from 0~ 3 000×10 -6 is reduced to 23 nA, and the Corresponding NOx concentration error is reduced to within 15×10 -6 . To further improve the accuracy of the sensor measurement, a calibration scheme is designed and tested in comparison with foreign NOx sensors. The results show that the sensor has a measurement error of 0~25×10 -6 in an environment with NOx concentration of 0~2 000×10 -6 under transient engine conditions, which verifies the feasibility of the scheme and well meets the requirements for monitoring NOx concentration in the exhaust gas, and provides a reliable solution for improving the accuracy of zirconia-based NOx sensors.