The invention discloses a device for on-line real-time detection of epitaxial film growth, and belongs to the technical field of semiconductor material manufacturing equipment. The device comprises an MOCVD reaction chamber, an optical component, a Raman scattering spectroscopy production system, a Raman scattering spectra of receiving system, a data analysis system, a photoelectric switch, a trigger signal circuit and an operating circuit. The device has the advantages of simple structure, easy coordination of parameters and obviously reduced real-time detection data bulk.