Provided is a method for treating an oil gas, which can realize high-efficiency separation for and recovery of gasoline components, C2, C3, and C4 components. The method first conducts separation of light hydrocarbon components from gasoline components, and then performs subsequent treatment on a stream rich in the light hydrocarbon components, during which it is no longer necessary to use gasoline to circularly absorb liquefied gas components, which significantly reduces the amount of gasoline to be circulated and reduces energy consumption throughout the separation process. Besides, in this method, impurities, such as H2S and mercaptans, in the stream rich in the light hydrocarbon components are removed first before the separation for the components. This ensures that impurities will not be carried to a downstream light hydrocarbon recovery section, thus avoiding corrosion issues caused by hydrogen sulfide in the light hydrocarbon recovery section.