The invention relates to a method and a system for increasing micro-grid operation reliability, which belong to the technical field of micro-grid power supply. The technical solution is as follows: after being connected in series with a photovoltaic inverter (2), a photovoltaic array (1) is connected with a micro-grid alternating-current bus (9), and after being connected in series with a wind turbine converter (4), a wind turbine generator (3) is connected with the micro-grid alternating-current bus (9); after being connected in series with a first energy storage converter (6), a storage battery pack (5) is connected with the micro-grid alternating-current bus (9), and after being connected in series with a second energy storage converter (8), a flywheel energy storage system (7) is connected with the micro-grid alternating-current bus (9); the micro-grid alternating-current bus (9) is connected with a micro-grid load (11). The invention has the following beneficial effects: the method and the system not only can carry out good smooth control to maintain the stability of micro-grid voltage frequency when the randomly fluctuating power of the output side of a distributed power supply fluctuates, but also can provide instantaneous power support in the process that a micro-grid is switched from grid connection to grid disconnection, thus realizing the smooth transition of the micro-grid from grid connection to grid disconnection and uninterrupted power supply for the micro-grid load.