Abstract: By optimizing the relations between activity and stability, diffusion and reactivity, cost and performance, a 3rd generation catalyst series for resid hydrotreating was developed by Research Institute of Petroleum Processing. Comparing with the 2nd generation RHT series of catalysts, this new series of catalysts exhibited an overall improvement in HDS, HDM and HDCCR performance, as well as much better stability for long-term running. The commercial results demonstrated that the new series of catalysts perform better than the reference catalyst series. Thus, it is helpful to increase the total economic benefit of the combined process of resid hydrotreating and catalytic cracking.