Abstract: The physical design and the computer simulation for inductive storage with a plasma erosion opening switch (PEOS) have been performed and plasma gun experiments have been conducted.In this paper the method for choosing parameters of the device including the circuit and PEOS is given in order to maximize the energy transfer from the accelerator to the load while obtaining the desired power multiplication.It is shown that in order to get a good performance of the system the product of injected plasma density n p and velocity vd must be large enough but with a low n _p and high v_d.In addition,radius of the cathode should be small to get fast opening.Our computer simulation also confirms this point of review,Furthermore the voltage,current and impedance history as a function ofthe input waveform,geometry,and PEOS parmeters are also given.The conical spiral gun which is a key unit of PEOS has been designed,built and tested.We have measured the gun ion current with a Faraday cup which is 60 cm from the gun.The carbon ion current density has a peak value of n_p-4×10¹¹/cm³ and the drift velocity of ion is v_d-5×10⁶ cm/s.