Integrating tunable characteristics and multiple functions into a single metasurface attracts more and more attention. Herein, a reconfigurable bifunctional metasurface is proposed to realize the switch between broadband polarization conversion and absorption. The switchable performance can be achieved by changing the conductivity of phase‐change material Ge2Sb2Te5 (GST) in the way of heating. When the conductivity σ of GST is set to 0 Sm−1, the metasurface is a polarizer that can transform the x‐polarized wave into the y‐polarized wave in the range of 0.53–1.22 THz. Moreover, its polarization–conversion ratio (PCR) is more than 90% from 0.60 to 1.15 THz. As σ increases to 1 × 105 Sm−1, the metasurface absorbs more than 75% of the incident wave from 0.44 to 1.34 THz, which means it is a broadband absorber. In addition, the performance of the metasurface is verified by simulation, experiment, and theory. Through comparison, the three results have a high fitting degree. The reconfigurable metasurface provides a new way to develop switchable photonic devices in the terahertz frequency region.