An ultrathin hot-rolled sheet strip with yield strength more than or equal to 500MPa level comprises the chemical components by weight: 0.02-007%of C, less than or equal to 0.50% of Si, 0.50-1.40% of Mn, less than or equal to 0.030% of P, less than or equal to 0.010% of S, 0.03-0.11% of Ti, 0.01-0.20% of Als, less than or equal to 0.005% of N, less than or equal to 0.004% of O, or 0.17-0.20% of C, less than or equal to 0.50% of Si, 0.50-0.90% of Mn, less than or equal to 0.030% of P, less than or equal to 0.010% of S, 0.03-0.08% of Ti, 0.01-0.20% of Als, less than or equal to 0.005% of N, less than or equal to 0.004% of O. The process comprises melted iron desulfuration, converter blowing, argon blowing, LF furnace refining, continuous casting, rotary descaling, soaking pit soaking, descaling, seven-frame finish rolling, stream cooling and coiling. The ultrathin hot-rolled sheet strip has the advantages that the addition of the alloying element is low, the mechanical property is as follows: the yield strength is more than or equal to 500MPa, the product thickness is less than or equal to 1.4mm, the sheet shape is good, the production flow is short, and excellent cold forming and welding performances are achieved.