In order to accurately calibrate micro scanning position and improve the spatial resolution of micro thermal imaging systems, the zero of micro scanning should be determined. The image registration algorithm was used to calculate the micro-displacement, and then a new adaptive zero calibration was presented based on geometric principle. Using telescopic thermal image to simulate the real system, different reconstruction methods were adopted to construct the simulation image and the real thermal microscope image before and after adaptive zero calibration. The results show that the method significantly improves the oversample reconstructed image quality, and increases the system spatial resolution. This method can also be used in other electro-optical imaging systems.