In order to improve extensibility and interoperability of distributed energy resources (DER) communication and control functions, the universal interface for DER communication and control based on IEC 61850-7-420 is presented for DER information model building and information exchange, and its specific design and implementation methods are proposed. The intelligent electronic devices for universal interface is developed, and the corresponding DER communication and control functions test is conducted based on multiple DER integration testbed. The research results show that the design and implementation methods of universal interface are feasible, and DER can achieve rapid and accurate information exchange for its status information, settings, control and measured/metered values. The universal interface can provide the effective techniques and solutions for DER system integration.