Indium-Tin-Oxide (ITO)/Selenium heterojunction solar cells which fabricated by vacuum deposition technique and annealing process has been investigated. Prior to the Selenium deposition, a thin tellurium layer (about $10{AA}$) was deposited onto the ITO layers to provide a sufficient mechanical bond between the Oxide and Selenium layers. The amorphous Selenium layer was deposited onto the Te-ITO layers, and then the crystallization of the amorphous Selenium was carried out using a hot plate at about $180^{circ}C$ for 4 min. Efficient Selenium solar cells with conversion efficiency as high as 4.52% under AM1 condition has been fabricated in polycrystalline Selenium layer ($6{mu}m$). The optimum data in manufacturing Se solar cell was listed in table.