Abstract As the problems of the energy and environmental issues have e increasingly prominent, the drawbacks of the power grid pattern with the features of large units, large power grids and high voltage in China es increasingly obvious. The Distributed Generation (DG) based on renewable energy technology developed rapidly in recent years. The operation of the distribution system is affected in many aspects for distributed generation is often connected to the distribution system. So distribution system protection is considered to be one of the biggest technical obstacles for the development of distributed system. With the interconnection of distributed generation of the distribution system the traditional current protection in the structure of the radiation work can not meet the requirements of protection which will result to protection tripping, blinding, reducing sensitivity and other issues. Therefore, it's necessary to study the impact on the protection caused by the connection of work and the distributed power and to find a suitable protection schemes. This article firstly details the technology of interface in the distributed power grid and control strategy of inverter-based distributed power .In the next ,the fault characteristics are analyzed, and structures the model of the PQ control inverter interfaced distributed generators with MATLAB/Simulink simulation, and make the simulation analysis on the three-phase short-circuit fault characteristics, which laid the foundation for study of the effect on the protection caused by the access of the DG to the work. In order to study the effect on the protection caused by the access of the distributed generation to the work, the fault current is analyzed when the PQ control inverter interfaced DG are put into the simple work. Then it explores the possible impacts on the protection work protection when the DG are put into the work from the respects of the access locations, the DG capacity and the types of DG .The s