Abstract: The test was conducted under artificial settings at low temperatures, 4 treatments were set as D1(CK),D2(-5℃),D3(-15℃),D4(-25℃), when the duration of low temperature were set as 6 treatment:3, 6, 9, 12, 15, 18 days, studies were made of changes of protective enzymes and their electrical conductivity in Prunus cistena excised shoots. The result showed that:SOD activity rose with the extension of the low temperature duration, D2 treatment was 25.60% higher than that of control with significant difference at the eighteenth day; With the duration of low temperature prolonged, POD activity first increased and then decreased, D2 showed no significant difference to control,and D3 and D4 were significantly higher than that of control; Conductivity of treatment D4 was always at the highest value during 3 to 12 days, D3 was highest during 15 to 18 days, all low temperature treatments were significantly higher than that of control. Comprehensive analysis suggested that continuous low temperature would make SOD and POD activities and conductivity of in vitro branch increase significantly.