690MPa thick steel plate for ocean engineering and manufacturing method of steel plate

The invention discloses 690MPa thick steel plate for ocean engineering and a manufacturing method of the 690MPa thick steel plate, and belongs to the technical field of steel for the ocean engineering. The steel plate comprises the following chemical components: 0.08-0.15% of C, 0.10-0.30% of Si, 1.0-1.50% of Mn, 0.03-0.04% of Alt, 0.02-0.06% of Nb, 0.03-0.06% of V, 0.010-0.02% of Ti, 0.1-0.5% of Mo, 0.5-1.6% of Ni, 0.1-0.4% of Cu, 0.4-1.2% of Cr, less than 0.01% of P, less than 0.005% of S, less than or equal to 0.12% of Nb+V+Ti, 0.0005-0.0017% of B, and the balance of Fe and inevitable impurities. Quenching temperature and tempering temperature are controlled strictly; the thickness of the produced steel plate is 50-120mm; and the microstructure of the steel plate is tempered sorbite and a little tempered bainite. The steel plate and the manufacturing method have the advantages that the lamellar tearing resistance and low temperature toughness are ensured; uniformity of the thick steel plate in the thickness direction is ensured; and the production cost is reduced.