High-strength steel plate with excellent cold bending performance and 690MPa-grade yield strength and manufacturing method of high-strength steel plate

The invention relates to a high-strength steel plate with excellent cold bending performance and 690MPa-grade yield strength and a manufacturing method thereof. The high-strength steel plate comprises the following components in percentage by weight: 0.04-0.08% of C, less than 0.10% of Si, 1.80-2.00% of Mn, 0.050-0.080% of Nb, less than or equal to 0.020% of V, 0.11-0.15% of Ti, 0.03-0.06% of Al, less than 0.10% of Ni, less than 0.10% of Cu, less than 0.010% of Cr, less than 0.010% of Mo, less than 0.001% of B, 0.001-0.005% of Ca, less than or equal to 0.012% of P, less than or equal to 0.002% of S, less than or equal to 0.002% of O, less than or equal to 0.004% of N, less than or equal to And the carbon equivalent CEV is less than or equal to 0.45%. The microstructure is that nanoscale TiC and NbC particles are distributed on a fine ferrite matrix structure in a dispersed mode, the grain size is larger than or equal to 7 grades, the high-strength steel is different from a martensite or bainite structure of t