Abstract: 【Objective】Clarify the aroma emission pattern of the Osmanthus fragrans cultivar ‘Boye Jingui' in order to provide the theoretical basis for the comprehensive development and utilization of Osmanthus fragrans.【Method】The aromatic components of ‘Boye Jingui' at different blooming stages and different time points in one day were analyzed by using headspace solid-phase micro-extraction(HS-SPME)and gas chromatography-mass spectrometry(GC-MS)methods. The variation in perianth microstructure during the blooming process of O. fragrans was observed by electronic scanning microscope and transmission electron microscopy.【Result】In the blooming stages of the ‘Boye Jingui' cultivar, the amount of aroma released was the lowest in the Xiangyan stage, rose in the initial blooming stage, arrived at its peak in the initial blooming stage, and then dropped rapidly in the final blooming stage. Meanwhile, the eosinophil matrix granule in the perianth cell of O. fragrans varied in morphology, number and location during the blooming period. The amount of floral scent released also showed the pattern of first increasing and then decreasing from dawn to dusk over one day, arriving peak at 9:00 and 15:00, and significantly decreasing at 7:00 and 19:00.【Conclusion】In the blooming stages, the aroma amount of the ‘Boye Jingui' cultivar released was the highest in the initial blooming stage; it is speculated that light intensity plays a key role in the diurnal variation of floral scent release, and that the eosinophil matrix granule could be an aroma releasing predecessor of O. fragrans.