Abstract: To better understand the relationship among break strength, expansion protein activity and abscission layer growth of wintersweet during the bud abscission period, and to study the influence of preservatives on wintersweet cut, break strength and expansion protein activity had been studied by dynamometer and protein recombinant in vitro respectively. Meanwhile, abscission layer formation had been observed based on paraffin section. Results showed that there was a negative correlation between break strength and the number of bud abscission. The amount of bud drop increased significantly while the break strength was less than 2.0 N. Expansion protein activity remained in lower level in earlier stage of vase-holding. In later stage, the activity increased rapidly and the break strength decreased significantly. Serious cell disintegration in the abscission zone resulted in fracture of abscission zone at the same time. Compared with CK, three preservatives had no significant differences on cut. Break strength and expansion protein activity were closely related to the abscission layer growth, and the former could be seen as the basis of division for the abscission layer growth, the latter played an important role mainly in the later stage of abscission layer growth. Three preservatives had no significant effects on wintersweet cut.