Abstract: The development of polyvinylidene fluoride( PVDF) membrane- based dot- immunoassay for convenience and rapid detection of sulfonamides in milk and pork liver samples was described. Based on the PVDF membrane,a membrane-based dot immunoassay was to detect sulphonamides,and the influence of envelope antigen concentration and antibody concentration factors on the immunoassay was studied. Using this method,the cut-off level of the sum of sulfadiazine(SDZ),sulfamerazine(SMR),sulfadimidine(SM2),and sulfametoxydiazine(SMDZ) were 50 μg/kg in milk and pork liver. The total concentration of SDZ,SMR,SM2 and SMDZ were determined in 20 milk and in 8 pork livers samples by both the PVDF membrane-based immunoassay and Ic-ELISA,and the results showed no significant difference with the HPLC. These results suggested that this method could be a useful on-site screening tool for the rapid detection of sulphonamides(SDZ,SMR,SM2 and SMD) in milk and pork liver samples without special instrumentation.