Wind　power　is　an　important　clean　energy　which　is　of　great　significance　to　human　beings.　However,　due　to　the　randomness　and　volatility　of　wind　power,　its　integration　will　bring　many　uncertainties　to　the　power　system.　If　the　wind　power　planning　can　not　be　coordinated,　the　wind　power　may　not　fully　be　sent　out　and　absorbed　A　joint　optimization　model　of　wind　power　and　thermal　power　can　stabilize　wind　power　fluctuations　and　improve　the　reliability　of　grid　connected　with　wind　power.　Particle　swarm　optimization　(PSO)　algorithm　is　used　to　optimize　the　transmission　line　capacity　and　pursuit　of　the　greatest　social　benefits.　This　paper　use　the　MATLAB　software　to　carry　on　the　simulation.　The　particle　swarm　optimization　algorithm　is　used　to　solve　the　optimization　model　of　combination　of　wind　power　and　thermal　power.　The　effectiveness　of　the　proposed　algorithm　is　verified　by　comparing　the　social　benefits　of　different　transmission　lines.