A set of transgenic detection methods and technology had been established to supervise and manage the commercial producing and selling of the transgenic papaya-Huanong No.1 Papain（Pn）was chosen as the endogenous comparison genes of papaya and primers were designed to detect the transgenic papaya and non-transgenic papaya. The regular PCR was established to detect the PRSV-Rep, exogenous CaMV 35S promoter sequence, NOS terminator sequence and the NPTⅡ of transgenic papaya. The clear bands were amplified when the annealing temperature was 40 ℃ to 60 ℃. The sensitivity of the single gene was 5×10－7 g . The Triple-gene-PCR detection system was created to detect three combination genes of NPTⅡ, Rep and CaMV 35S; or NPTⅡ, Rep and Nos; or NPTⅡ, Rep and Papain. And the Quad-PCR system was built to test four genes of NPTⅡ, Rep, CaMV35S and Nos as well.