High gain DC-DC converter plays a very important role in the process of grid connected photovoltaic power generation, fuel cell generation and so on.Therefore, it has very important practical significance to study high efficient and reliable high gain DC-DC converters.Up to now , a variety of boost DC-DC converters have come into being from different perspectives.According to the research status and basic principle of high gain transformation,high gain converter topology is divided into cascade connection of two-port,three level,switch -capacitor,interleaved parallel type based on three port,coupled-inductor , respectively.The composition of ideas and the performance of the converter are described in detail and a comprehensive overview of the course of the non isolated converter is carried out. Their merits and drawbacks are also briefly compared.This paper hasScertainSguidanceSmeaning in the topology structure of the new energy power generation system.