Abstract: The double anode electron gun is designed and calculated according to the requirements for the gyrotrons by this method, which combines synthesis with analysis.A set of computer program is made.The electrode shapes, electron trajectory and electron beam parameters are also given by the computer adided design.The electron gun has such characteristics as small velocity spread, good laminar flow and small volume etc. While the later is more suitable for operating at large current.It is applied in the experiment.The experiment of using the Gurotron show that the gun has advantages over other guns.