Abstract: Plastic scintillator detectors play a vital role in beam loss monitoring for high-power heavy-ion accelerators due to their high radiation sensitivity and rapid response characteristics. Accurate calibration coefficients, which vary with ion species and energy, are essential to ensure detector signals reliably quantify particle loss. Traditional calibration methods involving artificial beam loss generation, though direct and effective, incur significant costs when applied to diverse heavy-ion beams. This study employs the Monte Carlo simulation toolkit G4beamline to model beam loss scenarios and interactions between plastic scintillator detectors and various heavy-ion beams (hydrogen, carbon, nitrogen, argon), providing corresponding calibration coefficients. Experimental validation was conducted at the Heavy Ion Research Facility in Lanzhou (HIRFL): A Faraday cup precisely measured beam intensity, while adjacent plastic scintillator detectors simultaneously recorded loss signals. Data analysis demonstrates that Monte Carlo-derived calibration coefficients effectively characterize actual beam loss, confirming the feasibility of replacing online beam calibration with simulation-based approaches.