It developed a method to calibrate the foci- meter based on Talbot- Moiré interferometer, the calibration range of focal length up to 100 meters. Moreover, it introduced a foci-meter based on Talbot-Moiré interferometer. It includes a lens group and a laser source to generate laser beams with steady focal length and wavefronts which used to calibrate the foci- meter. The focal length of the lens group is measured by experiments taking advantage of a traceable lens.The following conclusions can be derived from experimental results: the uncertainty of this calibration method is acceptable.