Abstract: Green fluorescent protein (GFP) is a special protein of a single polypeptide chain with 238 amino acids derived from Aequorea victoria. A chromophore is formed autocatalytically on the nascent apoprotein’s backbone via posttranslational modification. The stable light-stimulated fluorescence is specifically independent and does not require cofactors, substrates or additional gene products. As a valid marker gene for bacteria, animal and plant genetic engineering, GFP is very sensitive for detection and is easily manipulated. What is more important, GFP can be detected in vivo, in situ, and in real time. This paper briefly introduces the biochemical and genetic properties of GFP and its application in the research of ecological monitoring of genetically modified organisms (GMOs).