Melamine and cyanuric acid were added into food and feed to elevate falsely assay results for protein content.It would be critically harmful to animals' health when the animals were fed with feed including melamine and cyanuric acid for a long time.Some incidents that melamine and cyanuric acid-contaminated food led to animals poisoning often occurred in recent years.Therefore,the effect of melamine and cyanuric acid toxicity attracted wide attention.In this review the physico-chemical properties,contact ways,metabolism,toxicity and pathogenic mechanism of melamine and cyanuric acid were discussed.