To address the issue of reduced oil recovery caused by CO₂ channeling during CO₂ flooding in low permeability reservoirs，a salt-tolerant and temperature-resistant plugging system with low initial viscosity and high CO₂ responsiveness was developed using erucamidopropyl dimethylamine （PKO‑E） and a counterion salt. The basic properties of the system，along with its injectivity and plugging performance under simulated low permeability reservoir conditions，were systematically investigated. Experimental results showed that at 70 ℃ and a salinity of 9 824.97 mg/L，the CO₂-responsive thickening system exhibited an initial viscosity below 4.7 mPa·s，which increased to above 600 mPa·s after CO₂ introduction，confirming its low initial viscosity and strong CO₂-induced thickening characteristics. The system also demonstrated high salt resistance and thermal stability-maintaining viscosities of 453.97 mPa·s at 70 ℃ with a salinity of 2.5×10 ⁴ mg/L and 512.26 mPa·s at 90 ℃ with a salinity of 9 824.97 mg/L. In plugging tests using low permeability cores，the injection pressure remained below 0.3 MPa，the plugging efficiency exceeded 96%，the gas reduction rate was above 96%，and the breakthrough pressure reached over 2.31 MPa，which proved the high efficiency sealing capability of the system for CO₂ channeling pathways in low permeability formations. This study provides a useful reference for enhancing oil recovery in such reservoirs.