The invention discloses ultra-low temperature steel in great heat input welding and a manufacturing method of the steel. The steel disclosed by the invention comprises the following components in percent by weight: 0.040-0.090% of C, less than or equal to 0.15% of Si, 1.10-1.50% of Mn, less than or equal to 0.013% of P, less than or equal to 0.0020% of S, 0.10-0.30% of Cu, 0.05-0.20% of Ni, 0.008-0.020% of Nb, less than or equal to 0.010% of Als, 0.008-0.013% of Ti, 0.0035-0.0065% of N, 0.001-0.004% of Ca, 0.0008-0.0020% of B and the balance of Fe and inevitable impurities. By adopting the simple combined design of alloy elements in the steel disclosed by the invention, the TMCP (Thermal Mechanical Control Processing) technology is optimized without the requirement of adding a great number of noble elements such as Ni and Cu, the excellent patent steel plate low-temperature tenacity is acquired and simultaneously the low-temperature tenacity of the HAZ (Heat Affected Zone) during large line energy welding is also excellent; and the uniform and excellent mechanical property, good welding property and marine atmosphere corrosion resistance are acquired, so that the steel disclosed by the invention is specially applicable to wind tower structures on the sea, low-temperature pressure vessels, ocean platforms and bridges.