Abstract Hydrate-based CO2 capture (HBCC) technology, which is a promising alternative method to CO2 capture, has received increasing attention in recent decades as it has mild operating conditions and unique separation mechanism. This paper summarises several available methods on improving the separation performance of HBCC technology, mainly including chemical additives and improvement of capture process. The chemical additives are generally divided into two classes: thermodynamic promoters (THF, TBAB, TBAF, CP, C3H8) and kinetic promoters (SDS, DTAC). In addition to the common single stage process, the multistage process and hybrid conceptual process coupled with membrane separation are developed to obtain more concentrated CO2. Then the evaluation indicators of separation performance are introduced: CO2 recovery and separation factor. Moreover, the separation performance of CO2 capture from either post-combustion flue gas or pre-combustion fuel gas is discussed and the development direction in the future is highlighted as well.