Abstract: Acute toxicity tests and mutagenicity tests ( Ames test, micronucleus test of bone marrow cell in mice and sperm shape abnormality test in rats) were used to explore the toxicological safety of tilapia fillets color retention with carbon monoxide ( CO) .The results showed that no death of NIH rats had been observed with the maximum tolerated dose for oral ingestion of tilapia fillets ( 26.4 mg/kg) in 14 days.The maximum value for Styphimurium anxotroph's back mutation strains of TA1535, TA1537, TA1538, TA98, and TA100 with 3 dose groups of 50, 500 and 5000 μg were 165 ± 7 that wasless than the minimum value for strains of Styphimurium anxotroph reverse mutation positive control groups ( p < 0.01) .The micronucleus rates of high, middle and low dose groups were ( 1.0‰ ± 0.5‰) , ( 0.3‰ ± 0.5‰) and ( 0.5‰ ± 0.7‰) respectively.No significant relationship between dose and micronucleus rates were observed.The t chromosome aberration rates of rats with high, medium and low doses were 5.5%, 5.9% and 4.9% respectively.There was no significant difference between control group and dose groups, which were significantly lower than positive control group ( p < 0.01) .The research results suggested maximum tolerated dose was higher than safety level 15 g/kg, and the Ames, micronucleus test of bone marrow cell and sperm shape abnormality test in rats were negative, indicating that tilapia fillets treated with CO had no acute and genetic toxicity.