MXene, as an emerging group of two-dimensional layered material, attracted more and more attention due to its extraordinary physical properties. In this study, a sandwich-like Co3O4/MXene (CMs) composite was prepared via a one-step heating method and used as a novel catalyst to activate peroxymonosulfate (PMS) for Bisphenol A (BPA) degradation. The sample (CM-20%) achieved an efficient catalytic activity with 95% removal of BPA at 20 mg/L within 7 min. Meanwhile, the parameters in the degradation process were optimized. In particular, CM-20% obtained excellent BPA removal efficiency in a wide pH range (4–10). Anions like NO3− and Cl− had a slight negative effect while HCO3− had a great negative effect on catalytic activity in CM-20%/PMS system. Notably, the catalyst exhibited a good performance after 5 consecutive runs and the leached cobalt ion was negligible. Electron paramagnetic resonance (EPR) analysis and quenching tests identified SO4− and OH were the reactive species. The pathway of degradation was also detected by analyzing its intermediates using LC-MS. This work provides a new field of MXene composite material for PMS remediation of organic pollutant and widens the application of MXene in environmental remediation field.