Optical biosensors based on different optical phenomena have been used widely over the past decade to analyse biomolecular interactions.With the advent of the nanoparticle technology,the probing of individual living cells,and the measuring of chemical species in specific locations within the cell for living cell sensing have become possible.Optical biosensors based on nanoparticles offer high sensitivity,specificity and rapid detection in the study of cancer cell or biomarker.In this paper,the applications of nanoparticles-based optical biosensor for the specific identification of molecules on the cell membrane surface for the study of cancer cells,the research of enzyme molecule in cancer cells and intracellular and the reactive oxygen,glutathione and physiological pH value in the smallest environment are reviewed.The prospect of this novel technique is also discussed.