The paraffin cut method was used to observe the morphological differentiation process of the flower bud of Osmanthus fragrans ’Wanzi Yingui’ and ’Duoya Jingui’. The result showed that the flower bud differentiation process lasted for about 3 months from bract primordial differentiation in the end of June to pistil primordial formation in the beginning of September. The morphological differentiation of osmanthus flower bud was divided into seven phases: bract differentiation phase, inflorescence primordium differentiation phase, single flower primordial differentiation phase, sepal differentiation phase of top flower, patal differentiation phase, stamen differentiation phase and pistil differentiation phase. The phase of bract differentiation and stamen differentiation were relatively long. The top flower of the inflorescence differentiation was earlier and slower than the lateral flowers. Later on all the top and lateral flowers finished differentiation almost at the same time. The prophase bud differentiation of ’Duoya Jingui’ was the same as ’Wanzi Yingui’ except for pistil differentiation.