In order to improve the standardized technical system of quantitative analyses for genetically modified organisms (GMOs) and protect China's bio-safety and reduce ecological risk, we establish a quantitative detection method for the genetically modified (GM) maize MON88017 using real-time fluorescent quantitative PCR. Meanwhile, the method is evaluated by several methodological indicators such as specificity, sensitivity, accuracy and uncertainty of measurement. The results show that the method has strong specificity in analysis of genetically modified maize MON88017. The mean value (1.54%) repeatedly measured for 29 times with the relative deviation of 2.7% was close to the real value (1.50%) and the variation coefficient of the measured value was 0.1. The tested recovery rate is 100% and the uncertainty of measurement is 0.096. 5 copies of the MON88017 molecular fragment can be detected at 97.5% confidence level. Consequently, the quantitative detection method established in this paper for the GM maize MON88017 has fairly high specificity, accuracy and sensitivity and this technology established in this paper can provide good technical support for the safety supervision of genetically modified organisms in China.