Abstract: The structure of plate-to-cone transition in vacuum transmission line is often used in the multi-modules Z-pinch drivers. This kind of transition will possibly result in an unacceptable power flow loss, particularly, when the transfer angle becomes bigger. In this paper, leaving out the invalidation of magnetically insulation and the loss in the dielectric, the finite difference method is adopted to simulate how variation of the transfer angle affects the power flow. The primary calculation and analysis show that the reflection caused by unmatched impedance will decrease the transmission efficiency with the increase of the transfer angle. The fast rise pulses will be distorted seriously in this structure, while the slow rise pulse will be hardly disturbed. It is favorable for effective pul