A new boronization technique focusing on the needs of the future large superconducting device has been developed in HT-7 tokamak. The first try on a tokamak gave very promising results. A fine homogeneous and hard a-B/C:H film was produced by a pulse ion cyclotron resonance frequency plasma. The film shows high adhesion, high thickness and longer lifetime. The ratio of B/C is about 3 up to a depth of 280 nm. X-ray photoelectron spectroscopy analysis shows that the B–B, B–C, C–C, C–O, and B–O bonds were formed during the boronization. The oxygen content in the film increases from 15% to 25% after 250 serious discharges, which demonstrated the strong oxygen gettering by the film. Good uniformity of the film in both toroidal and poloidal directions has been obtained by using long antenna on the high field side. The recycling of hydrogen was easily controlled by using helium rf discharge after boronization, and very strong wall pumping was observed. Plasma performance was significantly improved after boronization. A higher density limit and wider operation space were obtained. The strong hard x ray accompanied by high power lower hybrid current drive was suppressed dramatically. This gives direct evidence that the thin boron film serves as a protecting layer against the energetic particles, which is very important for future long-pulse-length discharge. This new technique has been proved to be very effective for conditioning future large magnetic fusion devices.