Through field experiments, the effects of four synergists on the control of peanut leaf spot disease were compared. The field trials were carried out according to the guidelines for the field efficacy tests of peanut leaf spot.The experimental results showed that the effects of different synergists on the control fungicide of peanut leaf spot disease were different. Among them, oligo-chitosan increased the most on the efficacy of the four agents, with an increase in efficacy of 5.59%-12.43%, followed by BioSoft and Cao-Jingle, with an increase in efficacy of 1.39%-8.62% and 0.09%-9.54%,respectively, and the difference between the two was not obvious. Ethylated methylated vegetable oils do not significantly improve efficacy. In the process of prevention and treatment of peanut leaf spot disease,when selecting synergists, the appropriate synergist should be selected according to the specific type of agent,and the oligo-chitosan has a synergistic effect on several agents in the test, and the scope of application is wide.