A large amount of emulsion is easily formed in the process of crude oil production due to the existence of active components, including asphaltene, resin, petroleum acid, and wax. Based on the composition and existing state of active components in crude oil, the influence mechanism of each active component on the emulsion stability was described. The interaction between active components and asphaltene with their influence on emulsion stability is summarized. Among the active components of crude oil, these are pointed out asphaltene is the main component of the interfacial film, and suitable resin with asphaltene can strengthen emulsifying effect. The results between carboxylic organic acid and asphaltene are various owing to different relative molecular weights, and the wax can enhance the strength of the interfacial film when they crystallize or interact with asphaltene. Meanwhile, current problems and future development directions are prospected.