Aiming at the problem that most existing chiral metasurfaces fail to achieve dynamic tunability while simultaneously possessing polarization conversion and absorption (ABS) functions, a switchable dual-functional chiral metasurface (CM) based on vanadium dioxide (VO?) is proposed in this paper. When VO? is in the insulating state, the CM exhibits linear polarization conversion (LPC) performance, with a polarization conversion ratio (PCR) exceeding 90% in the frequency range of 1.74-2.50 THz and a relative bandwidth (RB) of 35.85%. When VO? switches to the metallic state, the proposed design realizes ABS functionality, where the absorptivity is over 90% in 1.59-2.70 THz (RB=51.75%). The mechanisms of LPC and ABS are revealed by analyzing the distributions of surface current, electric field and magnetic field at resonant frequencies. In addition, the influence laws of geometric parameters, incident angle and polarization angle on the dual-functional regulation characteristics are discussed. The proposed design features advantages such as thin thickness and polarization insensitivity, and holds potential application value in the fields of stealth radomes, wireless communications and microscopic imaging.