Abstract: A compact long pulse generator was presented, whose spiral Blumlein line possessed inner magnetic conductor cylinder, central spiral cylinder and outer magnetic conductor cylinder. The spiral Blumlein line was charged by means of a built-in high coupling Tesla transformer, whose primary coil was adjacent to outer conductor cylinder and secondary coil was located between central spiral cylinder and outer conductor cylinder. Theoretic calculation of characteristic parameters, such as slow wave coefficient, switch closing current, variable factors describing wave transmission behavior on the interface of closed switch, was given by physical analysis of wave transmission on spiral Blumlein line. Numerical simulation of part of wave transmission courses on spiral Blumlein line was proceeded by