The infrared thermal imager can monitor the target temperature, which plays the role of accident warning and location confirmation, large-scale human temperature screening and so on. Due to the temperature drift caused by the change of ambient temperature and infrared radiation absorption, most of the infrared thermal imagers for temperature measurement need blackbody for real-time calibration, but the blackbody-based infrared thermal imagers are limited by the fixed scene and poor portability. To solve this problem, a temperature calibration and compensation method without blackbody was proposed. By deducing the principle of infrared temperature measurement, the prior relation between target temperature and radiation quantity was obtained with multiple blackbodies calibration, and for addressing temperature drift caused by the internal structure of the detector, the temperature compensation was realized by non-linear modeling based on Newton's cooling law. The experimental results show that the proposed methods have the long-term stability to keep the relative error of temperature measurement within 0.9%, reduce the average relative error by 64%, and realize the portable, real-time, stable and high-precision temperature measurement of miniaturized infrared thermal imager.