We present a catalog of distances for 19544 K-giants drawn from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR8. Most of them are located in the halo of the Milky Way up to ~120kpc. There are 15% K-giants without Sloan Digital Sky Survey (SDSS) photometry, for which we supplements with Pan-STARRS1 (PS1) photometry calibrated to SDSS photometric system. The possible contamination of the red clumps/horizontal branch are removed according to metallicities and colors before the distance determination. Combining the LAMOST spectroscopic metallicities with the SDSS/PS1 photometry, we estimate the absolute magnitudes in the SDSS r-band, the distance moduli, and the corresponding uncertainties through an Bayesian approach devised by Xue et al. for the Sloan Extension for Galactic understanding and exploration halo K-giants. The typical distance precision is about 11%. The stars in the catalog lie in a region of 4-126kpc from the Galactic center, of which with 6320 stars beyond 20kpc and 273 stars beyond 50kpc, forming the largest spectroscopic sample of distant tracers in the Milky Way halo so far.