We have demonstrated a regenerative harmonic frequency modulated(FM) mode-locking in a bulk Nd:LiYF4 (YLF) laser for the first time. After suppressing the mode competition between positive (up-chirped) and negative (down-chirped) modes using an etalon, a third-harmonic FM mode-locking based on a regenerative feedback loop was realized in a Nd:YLF laser. Stable, self-starting pulses were generated with a duration of 6.5 ps at 1-GHz repetition rate and an average output power of 240 mW at a 1-W laser diode pumping power.