Abstract: A PCR-based method and a immunological-based method were developed to detect extraneous genes in transgenic herbicide-tolerance soybeans and their processed products in this study.The primers for the gene of endogenous Lectin and foreign DNAs in Roundup Ready(RR) soybean,i.e.35S promoter(from cauliflower mosaic virus),NOS(nopaline synthase) terminator and CP4-EPSPS(5-enolpyruvylshikimate-3-phosphate from CP4) have been designed and synthesized.The detection limit based on qualitative PCR reaches 0.1% of transgenic content.Also,the CP4-EPSPSgene was amplified from RR soybean by PCR and expressed in E.coli.The anti-CP4-EPSPS antibodies were produced by immunized rabbits with the purified recombinant CP4-EPSPS protein, and used to develop western hybridization-based method in detecting the RR soybeans and their crude processed products.The detection limitation of this method is able to reach as low as 1% of transgenic components.These two can be cooperated to set up the standard methods for detecting genetically modified crops and their processed products.