The invention discloses a single-side compact disc protective box capable of preventing the luminous surface of a compact disc from physical wear and a compact disc reading-writing device for assorted use, and in particular relates to a mechanical compact disc fixing mechanism of the single-side compact disc protective box. Four groups of leverage disc fixing mechanisms are arranged at an extension area of the single-side compact disc protective box, each group of leverage is made by respectively arranging one end of a compact disc clamping body (2) and one end of a power body (3) at two sides of the axe center of a rotation mechanism (4), the other end of the compact disc clamping body (2) extends to a compact disc groove (8) and can clamp and contact the exterior edge of a compact disc (7); the power body (3) exposes from a singe-side compact disc protective box (1) and is corresponding to and contacts an extrusion body (17) of an automatic cartridge device arranged on a compact disc bracket (15) of a compact disc reading-writing device (14) for assorted use; the automatic extrusion device comprises two groups of extrusion bodies (17) which are correspondingly arranged at an interval; all the power bodies (3) of the single-side compact disc protective box (1) can be driven by once very short straight extrusion and slide of the extrusion body (17) to rotate the compact disc clamping body (2), thus finishing releasing the compact disc (7).