Hydroquinone (HQ) clathrate is one of the inclusion compounds formed from two or more molecular species and associated with the enclosure of guest molecules within hydrogen-bonded framework formed by the HQ host molecules. the structure of methanol-loaded HQ clathrate was checked by spectroscopy such as X-ray diffraction and Nuclear Magnetic Resonance. Especially the structural transition from methanol-loaded HQ clathrate to crystalline α-form hydroquinone was observed by in-situ Raman spectroscopy as a function of temperatures. The vibrational Raman bands at 1160 and 1600 cm-1 were used as an indication to determine the structural transition of the HQ clathrate. Temperature-dependent Raman measurements showed that the methanol-loaded HQ clathrate is stable at temperatures below 380 K and gradually transforms to the a-form of crystalline HQ between 380 ~ 410 K. At the transition region, we observed a dramatic decrease of the O-H stretching Raman band of methanol at 3627 cm-1, indicating the rapid release of methanol molecules from the HQ clathrate framework.