Abstract: In order to prevent environmental pollution from Ag+, it is necessary to develop a pretreatment solution without Ag+ for cut chrysanthemum. Having pretreated the cut flowers in different concentration of benzalkonium bromide (a germicide without Ag+) for different times, then transplanted into water and kept in the room at 20~25℃, we investigated the effect of benzalkonium bromide on preservation. Compared with other methods, the effect on preservation of the cut flowers, pretreated in 100 ml/L benzalkonium bromide for 3 hours, was obvious. The fresh flower weights increased slowly, few or none leaves were wilting after transplanted into water for 6 days. Etiolation of the leave slowed down and almost 90% leaves kept fresh after 12 days. The flower buds blooming speed also slowed down, 50% of flower buds were opened, petals were kept fresh, the stems of cut flower were unbent, and none flowers were drooped after 15 days. These results indicated that the cut flowers after pretreated in solution with 100 ml/L benzalkonium bromide for 3 hours, the vase life extended further than the other pretreatments.