The invention discloses a profiling-type garlic root-cutting machine and a root-cutting method thereof. At present, no reliable garlic root-cutting machine is existed in China, and the foreign garlicroot-cutting machine is complicated and expensive, and is difficult to adapt to the agronomic requirements of China. The root-cutting machine comprises a frame, a conveying mechanism, a profile cutting device and an intermittent combined driving mechanism. The transmission mechanism includes a top transport shaft, a bottom transport shaft, a chain drive assembly, and a discharge member. The profiling cutting device includes a profiling cutting bracket, a profiling mechanism, and a cutting mechanism. The profiling mechanism includes an unlocking shaft, an unlocking cam, an unlocking push rod, an unlocking slider, an unlocking tension spring, and a single garlic profiling assembly. The single garlic profiling assembly includes a profiling frame, a profiling wheel, a ratchet cover, a profiling compression spring, a ratchet block, a ratchet bar, and a positioning pull bar. The machine can achieve the same cutting depth effect on garlic with different heights.