In this paper, the development of Backward Bent Duct Buoy (BBDB) wave energy conversion technology in China is summarized. Novel ideas, new testing data and the improved performance of the BBDB conversion technology are presented. The latest large-scale model experimental results show that the peak wave-to-wire conversion efficiency of a new BBDB device is 42.0% under regular waves and it is 27.1% under random waves with the load of the battery. By comparison with the experimental and sea trial results of Japan's "Mighty Whale", the BBDB prototypes based on the experimental results of the new BBDB model present many advantages. If equipped with the latest air turbine, the conversion efficiency from pneumatic power to electric power of which is nearly 60% in sea trial, the efficiency from wave to wire of the new BBDB converter has the potential to exceed 50% in real sea waves, which is much higher than that of many other wave energy conversion technologies.