The invention discloses a low-compression ratio thick-gauge pipeline steel, the chemical composition and mass percentage of which are: C 0.03-0.07%, Si 0.10-0.30%, Mn 1.1-1.6%, Cr 0.1-0.3%, Ni 0.1 ~0.4%, Mo 0.10~0.25%, Nb 0.04~0.07%, V≤0.03%, Ti 0.01~0.025%, Al 0.01~0.045%, Mg 0.002‑0.0022%, using clean steel smelting, continuous casting, and slab heating , Three-stage controlled rolling, and ultra-fast cooling process. The matrix structure of the obtained steel plate is granular bainite and acicular ferrite, which has good strength-toughness matching and low yield ratio, and has excellent resistance to HIC and SSCC acid corrosion, and can meet the thickness specification yield strength ≥ 485MPa pipeline steel and service technical requirements for acid-resistant pipelines.