In　this　paper,　6　pieces　of　steel-concrete　composite　girders　with　externally　prestressed　tendons　were　tested　under　negative　moment　loading,　and　nonlinear　finiete　element　anaysis　were　also　conducted　to　explore　the　effects　of　concrete　strength,　degree　of　partial　shear　connections　on　the　ultimate　flexural　capacity,　slip　property　between　the　concrete　and　steel　and　stresss　increments　of　external　prestressed　tendons.　Some　key　conclusions　can　be　extracted　from　the　experiments　and　analysis　and　listed　as　follows:　(1)　The　change　concrete　strength　and　degree　of　shear　connection　make　little　influence　on　the　ultimate　flexural　capacity　of　externally　prestressed　steel-concrete　composite　girders　for　negative　moments.　(2)　The　slip　between　the　steel　and　concrete　and　concrete　cracking　may　effect　each　other　in　the　negative　moment　area.　The　change　of　degree　of　shear　connection,　concrete　strength　and　initial　effective　prestressing　have　small　impact　on　slipping.　(3)　The　proposed　nonlinear　FE　model　can　better　predict　static　behavior　of　prestressed　steel-concrete　composite　girders　in　the　negative　moment　area,　and　the　results　from　testing　and　FE　analysis　can　correlate　very　well　with　each　other.