The method relates to an 800 MPa-grade low-yield-ratio structural steel plate and a production method thereof. The steel comprises the chemical components in percentage by weight: 0.045 to 0.075 percent of C, 0.30 to 0.55 percent of Si, 1.55 to 1.95 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.0025 percent of S, 0.012 to 0.035 percent of Al, 0.15 to 0.25 percent of Cr, 0.15 to 0.3 percent of Mo, 0.2 to 0.4 percent of Cu, 0.2 to 0.4 percent of Ni, 0.008 to 0.04 percent of Nb, 0.008 to 0.04 percent of V, 0.008 to 0.03 percent of Ti, 0.0008 to 0.0015 percent of B, and the balance of Fe and inevitable impurities. The steel is subjected to RH vacuum treatment, ladle furnace (LF) external refining, full protection casting, a thermo mechanical control process (TMCP), and tempering heat treatment to form the steel plate with low yield ratio, high strength and high work hardening rate. The steel plate has the thickness specification of between 10 and 40 mm, the yield strength of more than or equal to 550MPa, the tensile strength of more than or equal to 800 MPa and the yield ratio of less than 0.70, and has excellent low temperature compact performance, cold forming performance and welding performance.