The invention provides a hot rolling wire rod of 1800 MPa level for a low-alloy structure and a manufacture method thereof. The hot rolling wire rod of 1800 MPa level for the low-alloy structure comprises the following chemical components by weight percentage: 0.30 to 0.40 percent of C, 2.0 to 3.0 percent of Si, 2.5 to 4.0 percent of Mn, 0.30 to 0.40 percent of Mo, and the balance of Fe and unavoidable impurities. The invention adopts Mn-Si-Mo line components, and produces a medium carbon hot rolling wire rod which takes fine acicular martensite structure as the characteristic through purification smelting, rough rolling, finish rolling and the controlled cooling technology. The hot rolling wire rod has the steel yield strength no less than 1600 Mpa, the tensile strength no less than 1800Mpa, the yield ratio no less than 0.80 percent, the elongation no less than 9.0 percent and the reduction of area no less than 40 percent.