Gas-liquid separation is widely used in various fields. And the centrifugal separator has been witnessed as a worldwide popularity owing to its small size and high efficiency. However, the uncertainty of the inlet flow pattern limits the wide application of centrifugal separators. In this paper, a new gas-liquid separator combining gravity separation and centrifugal separation was proposed for complex and unstable two-phase flow. In this study, the performance of the separator under different liquid flow rates with wide gas volume fraction range from 5% to 90% was investigated experimentally, and the phenomena occurred in the separator were also analyzed. The results show that the separator can keep high-efficiency separation in multiple flow patterns as long as the liquid level in the downcomer is at a reasonable position. Meanwhile, the lowest and highest allowed liquid levels were defined and measured by the pressure difference and a ruler. Furthermore, the bubble column in the downcomer was analyzed. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.