This application provides a polymer current collector, a preparation method thereof, and a secondary battery, battery module, battery pack, and apparatus associated therewith. The polymer current collector provided in this application includes polymer film layers, where the polymer film layers include a first polymer film layer and a second polymer film layer, a resistivity of the first polymer film layer is denoted as ρ1, a resistivity of the second polymer film layer is denoted as ρ2, and the current collector satisfies ρ1>ρ2. The polymer current collector in this application can induce to deposit of lithium metal from a low conductivity side to a high conductivity side, avoiding risks of depositing lithium ions on the surface of the current collector and thereby increasing cycle life of lithium metal batteries.