Herein,　we　developed　a　rapid　method　for　detection　of　genetically　modified　soybean　(GTS　40-3-2)　products　using　loop-mediated　isothermal　amplification　(LAMP).　A　crude　5-minute　extraction　method　was　established　for　DNA　extraction　from　soybeans　and　soybean　products.　LAMP　reaction　for　CaMV35S　promoter　was　optimized　and　the　fastest　threshold　time　(Tt)　was　14　min　with　4　mM　magnesium　ions　at　63　degrees　C.　A　portable　instrument　was　designed　to　perform　real-time　LAMP　in　the　field.　As　little　as　0.1%　GM　soybean,　specifically,　or　0.5%　GM　ingredients　in　Chinese　traditional　tofu　could　be　detected　in　30　min　from　sampling　to　results.　We　used　this　method　to　further　assess　other　five　soybean　products　to　determine　whether　they　contained　transgenic　ingredients　and　compared　the　results　with　those　obtained　using　PCR,　which　suggested　the　proposed　method　was　applicable　for　rapid　detection　of　genetically　modified　soybean　in　food　products.