Abstract—IEC61850 is the most complete communication standard in the field of substation automation. MMS (Manufacturing Message Specification) is the key to realize IEC61850, and libIEC61850 is an important method to realize IEC 61850 by MMS. This paper introduces the mapping relationship between ACSI (Abstract Communication Service Interface) and MMS, and analyzes the mapping process of libIEC61850 in detail. Finally, the application program that describes the use of libIEC61850 and test methods verified the correctness of the transplant.