A novel hydrocyclonewith guide vanes, named as axial hydrocyclone (AHC), is designed to tackle the problem of oil-water separation faced by most mature oilfields. Optimal design of the AHC is carried out by using numerical methods. The effects of guide vanes, cone angle, tapered angle and overflowpipe on the oil-water separation are discussed in this paper. The results show that a double swirling flow is generated in the tapered section where oil-water separation occurs. Both the cylindrical and the tapered section have important influences on AHC performance. On the basis of single factor results, response surface methodology is employed to optimize the AHC design. The experimental results indicate that the novel AHC has an excellent performance for the oil-water separation. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.