This study investigates the toxicity resistance of rice plants grown on acid sulfate soil in the Mekong Delta, focusing on enzyme activities of catalase, peroxydase, and phosphatase. Results indicate that higher toxicity levels impair enzyme function, particularly affecting phosphatase, while peroxydase activity increases in resistant varieties. The findings highlight the crucial role of these enzymes in helping rice plants recover from soil contaminants, underscoring the importance of selecting tolerant varieties for sustainable agriculture in toxic environments.