Abstract: Separation devices are the key equipment in the liquefied natural gas (LNG) pretreatment process of the offshore floating production system, and the distributions in the devices could make large impacts on the separation efficiency, especially under the specific conditions in the offshore oil/gas field, which will decrease the efficiency of the pretreatment processes. We review the overseas and domestic research status about the gas-liquid flow and mass transfer performances under sloshing conditions, analyze the characteristics of the gas-liquid separator, packed column and the purification process, and provide some research approaches for improving the separation efficiency of the floating equipment. According to the practical project, the current problems and the future research emphases of the offshore separation equipment are pointed out, which could offer advices for the offshore separator selection and optimization.