A deterioration detecting system for semiconductor process kits has a Raman spectrometer, an optical detecting unit, a Raman spectra database unit, and a controlling-computing unit. The optical detecting unit and the controlling-computing unit are both coupled to the Raman spectrometer. The Raman spectrometer detects a semiconductor process kit under detection through the optical detecting unit to obtain a scatter light having an excited Raman spectrum signal. The Raman spectra database unit stores a plurality of Raman spectrum signals corresponding to multiple known use hours, multiple known materials, multiple known material compounds, or multiple known material deterioration state, of the semiconductor process kit under detection. The controlling-computing unit compares the excited Raman spectrum signal and a threshold of the Raman spectrum signals accessed from the Raman spectra database unit and outputs a judgment signal relating to the deterioration state of the semiconductor process kit under detection.