A High Step-up DC/DC (HS) converter was proposed. It steps up the voltage by using a special structure, and the boost structure is composed of two inductors, a capacitor and two diodes. Combing the special boost structure with the double-switch boost DC converter, HS converter is obtained, which depends mainly on charging and discharging of the inductors and capacitors to realize the step-up function. In addition, Repeated HS (Re-HS) and Generalized HS (G-HS) converters were proposed. The voltage gain of the Continuous Conduction Mode (CCM) for HS converter was analyzed. The voltage gain, voltage stress and ripple current of HS converter was deeply studied and compared with other converters. The comparative analysis shows that the HS converter has the characteristics of high voltage gain, low voltage stress, and low current ripple. By building the actual circuit of the HS converter, the correctness of the proposed topology is verified.