As a branch of solvent extraction, synergistic extraction has been widely studied. In order to explore the mechanism of synergistic extraction, it is necessary to clarify the internal reasons of the extraction system and give the relationship between the micro and macro properties. Therefore, it is important to understand the synergistic extraction system and the influencing factors from the microscopic structure and internal movement of molecules. In this owrk, the mechanism of synergistic action between extractant, extractant and metal ions and the influencing factors were reviewed. It pointed out that the essence of synergistic extraction was the formation of hydrogen bonds, which led to the change of the structure and energy of extractant, thus improving the extraction effect. Synergistic extraction mainly includes two aspects: one is easier to generate stable extraction complex to improve the extraction efficiency; the other is to improve the separation performance by using the difference between extractant. The pH of the extraction system, the combination and proportion of different extractant, the concentration of extractant and the addition of neutral phosphorus extractant significantly affect the synergistic extraction process, and there are interactions among various factors. It will be one of the effective methods in the field of chemical research in the future to carry out theoretical prediction by simulation calculation, verify by experimental means, and characterize with modern analytical chemistry method. The theory is popularized to practice, so as to better guide the production.