800MPa-stage hot rolled TRIP steel based on CSP process and manufacturing method

The invention discloses 800MPa-stage hot rolled TRIP steel based on a CSP process. The 800MPa-stage hot rolled TRIP steel is prepared from the following chemical elements according to weight percent: 0.165 to 0.20% of carbon, 1.40 to 1.60% of silicon, 1.45 to 1.60% of manganese, 0.06 to 0.08% of phosphorus, less than or equal to 0.005% of sulfur, 0.015 to 0.060% of acid soluble aluminum and the balance of iron and inevitable impurities. A manufacturing method of the steel comprises the steps of smelting in a converter, refining, performing continuous casting on a sheet billet, soaking the continuous casting billet, descaling with high-pressure water, performing controlled rolling, performing controlled cooling and reeling. Economic C-Si-Mn-P composition design is adopted, and metallographic structures adopt 50 to 65% of ferrite, 20 to 40% of bainite and 7 to 15% of retained austenite; the yield strength is 500 to 550 MPa, the tensile strength is 800 to 880 MPa, the elongation A80 is 27 to 31%, and the steel has good strength and plasticity matching.