The feasibility of a novel and efficient diagnostic method for liver fibrosis using Raman spectroscopy is studied. Confocal Raman spectroscopy (CRS) is utilized to monitor the molecular changes of hepatic stellate cells (HSCs) in vitro as well as in vivo activation. In vitro activation was induced by growth in uncoated plastic plates, while the in vivo activation is induced by a single intraperitoneal injection of carbon tetrachloride . The biochemical changes of HSCs during activation such as the loss of retinoid, the increase of -helical protein, and the increased production of extracellular matrix proteins are observed by CRS. A user-friendly autoclassifying system is also developed to classify Raman spectra of liver injury tissues with a 90% accuracy rate. Raman spectroscopy combined with a fiber optical probe could be potentially accomplished for in vivo detection, which can lead to a novel and efficient diagnosis for liver fibrosis.