In order to solve the problem of poor target location accuracy in wide-field infrared alarm system, a polynomial fitting method based on active markers was used to extract target location in wide-field infrared alarm system. A high-temperature ceramic heating plate was used to simulate an infrared target, and a high-precision 2-D turntable was used to obtain the corresponding data point set of the camera’s attitude angle and the target center coordinates, and a binary high-order polynomial was used to fit the target orientation information. The high-precision azimuth extraction of the target in the large-field infrared warning system was realized. The experimental results show that the angle error of the fitting method is within ±0.1°, and the target positioning accuracy is high. This result is helpful for target azimuth extraction in large-field infrared imaging.