The technology of directional reaming while-drilling for oil and gas wells is mainly used to optimize the well structure, improve the cementing quality and avoid drill pipe sticking caused by wellbore shrinkage. The applicable rock breaking tool for this drilling technology is reaming bit. The research and development of a novel reaming bit was conducted based on the actual demands of directional reaming while-drilling for deep wells in Tahe oilfield. Based on the optimization design of reaming structure, crown profile and cutter distribution, the CK306B PDC (polycrystalline diamond compacts) bit for directional reaming while-drilling was developed. Specifically, the basic reaming structure was designed with two-stage, and the crown profile of the pilot bit was designed as a slight-raised curve and the cutters were distributed on the basis of the self-balancing principle. The simulation analysis of stability and hydraulic characteristics of novel reaming while-drilling PDC bit was carried out. Field application in directional reaming while-drilling for deep wells in Tahe oilfield showed that the bit had a good performance, wherein, the reaming diameter was larger than 170 mm while the build-up rate reached 9.9°/30 m, which indicated that either the reaming ability or the build-up ability of the bit satisfied the engineering requirement. Moreover, the average footage of reaming bit was 93 m and the ROP (rate of penetration) of the bit was 1.24 m/h, which were 50% and 4% higher than foreign congeneric bits used in similar well section, respectively. The research result shows that it is feasible to use the novel PDC bit for directional reaming while-drilling in deep-well because the novel bit can meet both the requirements of well track control and directional reaming. Besides, the lateral imbalanced coefficient of the novel reaming bit can be controlled within 0.05, which will improve the stability of the bit, reduce the bit failure risk and prolong service life of the bit.