Objective Effects of four chemical preservatives,acetic acid,citric acid, sodium chloride and sodium nitrite on the viability of Clonorchis sinensis metacercariae in vitro were studied. Methods Freshwater fish meat infected by Clonorchis sinensis metacercariae was digested and metacercariae were isolated from hydrolysis extract. Metacercariae were quantitively imbibed into PBS buffer containing different concentrations of food preservation chemicals. The viability and morphological structure of metacercariae in different chemicals were studied. Results The results showed that there was no significant effect from citric acid,sodium chloride or sodium nitrite on the viability of encysted metacercariae. 5% of acetic acid and 10% of alcohol solution could affect the movement of encysted metacercariae and eventually cause their death while it costed a long time treatment. Low concentration of alcohol could stimulate metacercariae and larvae activity, but vitality reduced with prolonged treatment. ConclusionOther non-heated treatment methods and their effects were still worth further study. \=