In this study, the catalytic performance of Photo-Fenton and sono-Fenton processes were tested on Acibenzolar-S-methyl fungicide. UV light source and ultrasound irradiation source (20 kHz of the frequency with a maximum of 125W power output) were used for Fenton-based reaction. The sono-Fenton process is the most effective in ASM degradation with a 100% degradation rate within 20 min compared to photo-Fenton, Fenton, photolysis, and sonolysis processes that achieved only 90%, 52%, 43% and 19%, respectively. The investigation shows that ultrasound irradiation has accelerated the efficiency of the Fenton process by increasing the hydroxyl radicals •OH generation. The kinetic study was carried out under different pH conditions, ferrous ions concentration and hydrogen peroxide dosages. The result showed that the optimum condition for acibenzolar-s-methyl degradation is at acidic pH medium, low concentration of hydrogen peroxide and ferrous ions. The contaminant was monitored with high-performance liquid chromatography. A transformation mechanism pathway of the sonochemical oxidation was suggested based on gas chromatography/mass spectra analysis.