Abstract: Optical molecular imaging(OMI)is one of the rapidly developing biomedical imaging technique employing different technologies, such as optical molecular probing, imaging and nanotechnology to monitor a local real-time non-invasive qualitative or quantitative dynamic studies both in vivo and in vitro. OMT′s advantages, i. e. high sensitivity and specificity, especially in vivo studies, make it suitable for diagnosis, drug tracking in preclinical research and development of new drugs. Thus, it is regarded as a powerful real-time in vivo monitor. This paper discusses the latest advances in the use of fluorescent probes and nanomaterials in optical molecular imaging and its application in the diagnosis and treatment of diseases and in the studies of pharmacology and tumor biology.