In industrial applications, it is common to use multiple mini-hydrocyclones in parallel to improve separation precision. Maintaining the uniformity of flow distribution and the low pressure drop of the mini-hydrocyclone group becomes a major challenge. This is because that any non-uniformity reduces the separation performance and that high pressure drop increases the system's power consumption due to increasing of pump power. In this paper, based on the theoretical analysis in our previous work (Huang et al., 2013), we performed a series of experiments in a UU-type mini-hydrocyclone group. It aims to acquire the characteristics of pressure drop and flow distribution, and to evaluate the separation performance in a laboratory scale. In single-phase experiments, it was observed that the non-uniformity degree of pressure drop and flow distribution was the lowest for an inlet pressure of 0.10 MPa, and a relatively uniform pressure drop and flow distribution were respectively obtained with the maximum fluctuations of 7.2% and 3.6%. In solid liquid separation experiments, the mini-hydrocyclone group was employed to separate the catalysts from the carrying fluids. As the catalyst concentration is increased, the separation efficiency of the mini-hydrocyclone group gradually increased as well, from 74.8% to 82.6%. Furthermore, the fish hook phenomenon existed in the grade efficiency curve of the mini-hydrocyclone group. The cut size d(50) ranged from 1.78 mu m to 1.92 mu m, in good agreement with that for single mini-hydrocyclone. Results indicated that the mini-hydrocyclone group can meet the requirements of satisfying separation efficiency and smaller cut-size precision in industry. (C) 2015 Elsevier B.V. All rights reserved.