This paper numerically investigates the jump heights of overhead transmission lines after iceshedding by the finite element method, and simulates the dynamic responses of the transmission lines, with different structure parameters, in different iceshedding conditions. Based on the results, it obtains the quantitative relations between the jump height of conductor and the amplitude difference of the two static states of the conductors before and after iceshedding, and proposes a simplified formula for the jump height of conductors in continuous span after iceshedding for the determination of the clearance distance between the conductors at different phases in the design of high voltage transmission lines located in heavy ice zones.