Abstract: A new oscillating system of glucose(Glu)-BrO_3~--acetone(Act)-H_2SO_4-Mn~(2+) has been reported. In this homogeneous Belousov-Zhabotinsky (B-Z) type oscillation, saccharide was used as a organic substrate. The roles of glucose and acetone in this oscillation have been investigated. According to the reaction products and the effects of many factors on the oscillation, a mechanism for this oscillation has been proposed in which both Br_2 and Br~- are the contolling factors.