[Objective]In order to establish a suitable pretreatment method for immunochromatographic detection for tetrodotoxin.[Methods]In this study,the ultrafiltration technology was applied to optimize the pretreatment.The magnetic immunechromatographic test strip established by our laboratory was used for evaluation.[Results]The results showed that the treatment of centrifugation at 4000r/min for 10min is optimized with a cut off molecular of 10Ku.This method was suitable for immunochromatographic assay with good recovery (92.4-126.0%).Also,the concentration of protein in the solution reduced after pretreatment.[Conclusion]This study provides technical support for rapid on-site test oftetrodotoxin.