Abstract: The wavelength calibration of high resolution astronomical spectrographs with a femtosecond optical frequency comb can significantly increase the accuracy of radial velocity measurements. This provides a powerful research tool for various cutting-edge scientific problems, such as the detection of earth-like planets, the determination of the expansion of the universe, and the measurement of fundamental constants. With reference to the recent developments in radial velocity measurements and frequency combs, we describe the principles of such techniques and discuss the future development of astro-comb wavelength calibration for high resolution astronomical spectrographs.