Fabry–Pérot (FP) etalon is an important instrument for high-precision wavelength calibration. Combined with white light, the FP etalon can generate dense and nearly equally spaced frequency peaks, having an advantage in short-term calibration over thorium-argon lamps. However, owing to variations in the cavity’s physical parameters, its resonant frequency will undergo slow drift, resulting in a significant decrease in long-term calibration precision, even strict environmental control cannot completely eliminate this effect. Therefore, equipping drift tracking systems for the FP etalon represents a valuable approach to improve long-term accuracy. FP cavities with meter-level lengths have been fabricated using Anti-Resonant Hollow Core Fiber (AR-HCF), which facilitates the realization of long cavity lengths while maintaining low temperature sensitivity. The drift tracking system is constructed with the External Cavity Diode Laser, rubidium absorption cell, and AR-HCF FP cavity. The experimental results show that when the length of the AR-HCF FP cavity reaches above 1 m, it can effectively capture the local characteristics of laser frequency scan and achieve an accuracy of MHz-level.