The invention provides a method and system for controlling a wind power plant. The system comprises a server and client sides. The server comprises a storage unit, a grouping unit and a strategy sending unit, wherein the strategy sending unit is used for sending group strategies of groups corresponding to the client sides to the client sides according to grouping results of the storage unit. Each client side comprises a strategy receiving unit and an adjustment unit, wherein parameters of power generating devices connected with the client sides are adjusted by the adjustment units to be power generating device parameters carried in the grouping strategies received by the receiving units. According to the system for controlling the wind power plant, windmills of the client sides are divided into a plurality of groups according to differences of external conditions, then the different group strategies are formulated according to conditions of each group, different environments of the windmills are flexibly used for adjusting device configuration, and therefore power generating efficiency is improved.