An astronomical laser frequency comb (astro-comb), which will be applied as a calibrator on the high resolution spectrograph of the 2.16-m telescope in Xinglong Observatory, is introduced. The astro-comb is based on an ytterbium-doped fiber laser frequency comb. By mode filtering, the mode spacing of the comb is increased to 25 GHz, which matches the resolution of the astronomical spectrograph. After spectral broadening and flattening, the spectrum span increases to more than 270 nm in visible range, the spectrum flatness maintains within 1 dB for a long time, and the side mode suppression ratio reaches 42 dB. The theoretical calibration precision of the radial velocity for the astro-comb reaches cm/s level, which meets the requirements for searching the earth-like extrasolar planets and directly detecting the acceleration of the cosmic expansion.