Abstract: The matrix effect of 18 pesticides on 5 edible fungi substrates was studied in this paper. By taking pleurotus mushroom, oyster mushroom, tremella, mushroom and double spore mushroom as the research objects, they were added with 18 pesticides at the concentrations of 0.05, 0.10 and 0.20 μg·mL^-1, respectively. The methods of QuEChERS combined with HPLC-MS/MS were used for the determination, and finally the matrix effects of 18 pesticides in the five edible fungi were evaluated by the peak area ratio of substrate standard point to solvent standard point. The results showed that the 18 pesticides mainly showed the substrate weakening effect in 5 substrates, and different supplemental levels had no significant effect on the matrix effect intensity of pesticides. The matrix effect of phorate and phoxim in pleurotus mushroom was the most significant, and the maximum value of | ME | was 47.9% and 35.81%, respectively; The ME of carbendazim in pleurotus mushroom, oyster mushroom and tremella ranged from -33.30% to -22.25%; The ME of abamectin in pleurotus mushroom and mushroom ranged from -28.44% to -20.11%; The ME of 3-hydroxycarbofuran and phorate-sulfoxide in mushroom ranged from -26.82% to -23.90% and -34.37% to -24.28%, respectively; The ME of methomyl in pleurotus mushroom ranged from -32.68% to -27.20%, with medium matrix effect. All of the 18 pesticides in double spore mushroom showed weak matrix effect. When HPLC-MS/MS was used to determine the residues of 18 pesticides in 5 kinds of edible fungi, including pleurotus mushroom, oyster mushroom, tremella, mushroom and double spore mushroom, in addition to abamectin, carbendazim, methomyl, 3-hydroxycarbofuran, phorate-sulfoxide, phorate and phoxim, the matrix effect of other pesticides could be ignored, and only the standard curve of solvent was prepared for quantification.