Abstract: C-type lectin of Scophthalmus maximus (SmLec1) plays an important role in the non-self innate immune system. We analyzed the activity characteristics of SmLec1, and the effect of environmental stress on its expression and regulation, and explored its potential function and response in turbot innate immune system in culture environment. In this study, the molecular mass of the SmLec1 with recombinant protein was found to be 19 ku as shown by SDS-PAGE, and the target protein was obtained after purification. SmLec1 showed agglutination activity against Vibrio anguillarum and Edwardsiella sp. in the six kinds of selected bacteria to test SmLec1 bacterial agglutination activity. On this basis, eight sugars were taken for the inhibitory agglutination studies. Among the carbohydrates tested, lactose, D-xylose, D-fructose, sucrose and D-mannose effectively inhibited the agglutination activity of SmLec1. In physical and chemical factors (pH, high temperature), the activity of SmLec1 was inhibited at pH < 7, T > 37℃. QPCR was performed to examine the relative expression of the SmLec1 in V.anguillarum challenge, the expression level of liver was relatively increased after pathogenic stimulation, the highest at 6 h, then gradually began to decline and returned to its original level at 32 h. Expression of SmLec1 in high temperature stress was analyzed by qPCR, and results showed that the expression of liver mRNA starts to rise from 19℃, and showed a decreasing trend from 22℃ to 27℃, while expression of other tissues did not change significantly. The impact of salinity stress on expression was not significant. The study could provide a scientific basis for further study of antibacterial mechanism and immune mechanism of SmLec1.