A solar concentrator which is a closed chamber with transparent wall, which is formed into a bulb structure; the bulb structure forms a sealed cavity where vacuum can be formed and the gases with certain compositions can be filled in; the bottom portion of the chamber wall is shaped into a parabola; the bottom portion of the said parabola wall is shaped into a CPC; the center part of the top portion of the chamber is shaped into a concave parabola, and the curvature of the said concave parabola is opposite to the said bottom parabola; a reflective layer is coated on the inner surface or outer surface of the said bottom parabola and the said CPC; a reflective layer is coated on the inner surface or outer surface of the said top concave parabola, wherein the incident light, which penetrates through the top transparent wall, will be reflected and concentrated by the bottom parabola to the top parabola, then reflected by the top parabola to form collimated beam light, and the beam light is collected with the assistance of the said CPC.