The ice-shedding way of iced conductors affects the dynamic response of transmission line system.In this paper，a finite element model of 4 towers and 5 spans is established by numerical method，and the ice is simulated by additional ice element method.The dynamic responses of the structure are analyzed when two-layer ice at mid-span of the middle conductor peels off at the same time and at different time with different thicknesses.The results show that the maximum rebound height，unbalanced tension and wire tension induced by one time ice-shedding are 24%，17% and 14% lower than those by ice-shedding at different time，respectively.The maximum rebound height of the system occurs when the second layer ice peels off and the conductor moves to the lowest position at the same time.The structure exhibits the same stable vibration state regardless of the interval time of the two ice layers shedding.When the thickness of outermost layer accounts for 3/5，the effect of ice layers shedding is minimal.The conclusions obtained by ice layer shedding research show that the values of ice-shedding load based on the assumption of one time ice-shedding are conservative，and there is some space for optimization.