Objective To establish a zebrafish larva model for identifying antioxidants and screen candidate substances.Methods Zebrafish larvae with 3 d post fertilization （dpf） were treated with the fish culture water containing 12 known antioxidants， 2 oxidants and 4 candidate substances for 20 h. The maximum tolerant concentration （MTC） was determined by the acute toxic effect including death. With the highest dose of MTC， different dosages of tested substance were used to treat 3dpf larvae respectively， and the reactive oxygen species （ROS） indicator CM-H₂DCFDA was added to the water at the same time. After 20 h treatment， fluorescent density was detected to calculate ROS clearance rate.Results Eleven tested known antioxidants showed lower fluorescent density in treated zebrafish larvae compared to the control， which suggested their ROS clearance potency. Two oxidants increased the fluorescent density， and three of four candidate substances were found to decrease fluorescent density in zebrafish larvae.Conclusion The study provided a sensitive test system for screening candidate antioxidants. The system was used to screen the products developed in the laboratory， and the results showed that it had certain application value.