Green Fluorescent Protein (GFP) and its mutants, as reporter genes, are widely applied in the regulation of gene expression, spatial location of protein, interaction between biological molecules, transgenic animal, evaluation of drug effect, and study of drug action mechanism, infinitely promoting the development of modern biology. With the constant progress of optoelectronic information techniques, Optical molecular imaging techniques, based on the fluorescent report genes, will lead to the real time visualization of molecular and cellular events in the different levels such as cell, cell network, tissue, organ, and body, and thus play an important role in the early diagnosis of dread disease as well as drug discovery and development.