Under　the　background　of　interconnected　regional　power　systems　and　long-distance　power　transmission　of　large-scale　wind　farms,　a　method　to　design　wide-area　damping　controller　is　proposed.　Utilizing　alternating　Krylov　subspace　algorithm,　the　order　reduction　of　the　interconnected　power　grid　is　implemented,　thus　the　trouble　of　processing　two　high-order　Lyapunov　equations　can　be　avoided.　On　this　basis,　considering　the　coordinated　damping　control　between　synchronous　generators　and　wind　farm,　it　is　put　forward　to　perform　coordination　and　optimization　of　controller　parameters　by　mean-variance　mapping　optimization　algorithm,　and　an　idea　of　gain　scheduling　is　proposed　to　solve　the　robustness　of　damping　controller　under　various　operation　modes　of　the　interconnected　power　grid.　The　feasibility　of　the　proposed　method　is　verified　by　results　of　case　study.