The thick steel plate for low temperature use and capable of being welded in superhigh energy has the material comprising C 0.030-0.050 wt%, Si not more than 0.2 wt%, Mn 1.50-1.80 wt%, P not more than 0.01 wt%, S not more than 0.002 wt%, Nb 0.010-0.020 wt%, Als 0.040-0.060 wt%, Ti 0.008-0.012 wt%, N not more than 0.0035 wt%, Ca 0.001-0.005 wt%, B 0.001-0.003 wt%, and Fe and inevitable
impurity for the rest, with Pcm not more than 0.18 wt%. The present invention has low
alloy steel as basis, properly raised Als content, C / Mn ratio of 0.020-0.050, Ti-B microalloying, Ca or REM treatment, Ti / N ratio of 3.0-3.5, optimized TMCP treatment, microscopic structure comprising small amount of ferrite and diffused
bainite crystal of average
crystal grain size below 15 micron, excellent mechanical performance and
welding performance, and is especially suitable for being used as high strength ship
deck, low temperature pressure container, offshore platform, etc.