An environmentally friendly, water-based temperature-responsive gel plugging agent was developed. The gel exhibits an initial viscosity of less than 5 mPa · s at room temperature, enabling easier injection compared to conventional solid particle plugging agents. Laboratory experiments demonstrated that the gel can rapidly form a stable gel structure under simulated reservoir temperature conditions, providing effective temporary plugging. Rheological measurements conducted at 75 °C and a shear rate of 4.3 s−1 showed that the maximum viscosity reached approximately 6000 mPa · s. Core flooding experiments further confirmed that the system could achieve a maximum plugging pressure gradient of no less than 80 MPa · m−1. The gel can be fully broken at 75 °C using kerosene at a 1:4 volume ratio (kerosene: gel), resulting in a clear, residue-free breaking fluid with a final viscosity below 4 mPa · s.