The invention belongs to the technical field of medicines, discloses a new crystal form of telaprevir and a preparation method thereof. The new crystal form of telaprevir shows characteristic diffraction peaks on an X-ray powder diffraction pattern represented by 2theta + / - 0.2 degrees at 10.78, 11.62, 18.04, 20.90, 23.12, 27.72, 31.00, 31.90, 32.86, 33.44, 37.30, 46.78 and 47.10, which is completely different from the prior art. The invention also discloses a preparation method of the new crystal form of telaprevir. The preparation method is simple, easy to operate, high in yield and purity and mild in reaction condition, and is suitable for large-scale production.