The invention relates to a TEC-based thermal infrared imager automatic correction method and device. The method comprises the steps of: in a calibration process of the thermal infrared imager, measuring a suspected pixel of the thermal infrared imager in each temperature range, adopting the suspected pixel existing in each temperature range as a dead point, and enabling the rest suspected pixels to serve as unstable pixels of each temperature point; in the using process, acquiring an image of the thermal infrared imager by a processing circuit, completing non-uniformity correction, acquiring the dead point position and acquiring a current temperature; searching an unstable pixel according to the current temperature; directly compensating the dead point position in the image; and judging whether the unstable pixel is a blind pixel or not, if so, performing compensation, and otherwise, not performing processing. According to the method, dead point and unstable pixel calibration is carried out on all temperature points, meanwhile, non-uniformity correction is completed, in the using process, blind pixel judgment does not need to be carried out on each image, corresponding compensationmethods are directly adopted for dead points and unstable pixels for compensation, processing is easy, and the real-time performance is good.