The invention discloses a database universal accessing method for a micro-grid monitoring system. The method includes the following steps of firstly, defining a universal database access class; secondly, obtaining a dynamic chained library for each specific database type, and obtaining universal plug-in functions corresponding to all the database types in the dynamic chained libraries; thirdly, dynamically loading the dynamic chained libraries corresponding to the types of the databases and matching the universal plug-in functions to the plug-in functions of the types of the databases in a plug-in mode according to the input database types through database connection functions in the database access class. By means of an objected oriented technology, after various database interface accessing methods are analyzed, the universal database access class is abstracted and extracted, database interface accessing functions for database opening, database closing, SQL sentence executing, database transaction operation and the like are uniformly provided outwards, and the interface functions are matched for all the databases on the bottom layer in the plug-in mode.