Based on the high theoretical accuracy of the Edlen formula method, the value of air refractive index is calculated according to parameters, such as temperature, humidity, and atmospheric pressure, which are measured by the small digital sensor. Aiming at the problem of insufficient accuracy in traditional method, we propose a method based on the second class standard platinum resistance thermometer and the pressure sensor to calibrate and correct the measured values of digital sensors, and use the temperature value to correct the atmospheric pressure, which can improve the accuracy of air refractive index. We use the revised sensor in the measurement, and the experimental results show that the precision of air refractive index reaches to ±5.13×10 -8, which is closed to the theoretical accuracy of 10 -8 obtained by Edlen formula. Compared with the results of distance ranging method, the accuracy of measured air refractive index reaches to 10 -7. The sensors can be widely used in the air refractive index measurement applications which need miniaturization.