Recent advances in Ruddlesden-Popper (RP)-layered nickelates have revealed a remarkable superconducting transition above the boiling point of liquid nitrogen under high pressure. Here, we report a theoretical investigation of RP cobalt oxychloride, which shows a correlation-driven metal-insulator transition. Strong hybridization between Co d orbitals and O p orbitals is identified close to the Fermi level. Upon incorporating enhanced electronic correlations, the Co d orbital emerges as the dominant component at the Fermi level with partial filling. Regarding the magnetic orders, our results shows the G-type AFM ground state. Notably, our calculations predict an insulator-metal transition under high pressure, establishing RP cobalt oxychloride as a promosing candidate for studying correlated transition metal compounds with potential magnetism and superconductivity.