Well　dispersed　Cu2O　hollow　microspheres　consisted　of　Cu　2O　nanoparticles　were　quickly　synthesized　in　aqueous　solution　at　room　temperature　(25　°C)　with　polyvinylpyrrolidone　(PVP)　as　surfactant.　The　influences　of　the　reaction　time,　PVP　amount　and　pH　value　of　NaOH　solution　were　studied.　The　formation　mechanism　of　Cu2O　hollow　spheres　is　that,　with　the　modification　and　steric　effect　of　PVP　molecules,　Cu2O　nanoparticles　aggregate　to　form　loose　aggregations　and　then　quickly　transform　to　hollow　spheres　through　Ostwald　ripening.　Formation　of　loose　aggregations　is　the　key　to　the　fast　synthesis　of　hollow　spheres　at　low　temperature.　The　application　of　Cu2O　hollow　microspheres　in　DNA　biosensor　was　also　investigated.　The　hollow　Cu2O　microspheres　greatly　enhance　the　immobilization　of　the　DNA　probe　on　the　electrode　surface　and　improve　the　sensitivity　of　DNA　biosensors.　©　2009　American　Chemical　Society.