The invention discloses a method for producing a high-toughness ultra-thick plate by using a continuous casting blank, and belongs to the technical field of rolling and thermal treatment processes for producing an ultra-thick steel plate by using the continuous casting blank. The rolling process is characterized in that: the heating temperature is between 1,150 and 1,250 DEG C, and the heating speed is controlled to be 0.8 to 1 min/mm; the rolling is controlled by adopting an austenite recrystallization area and an austenite non-recrystallization area, when the thickness is 1.5 times more than the thickness of a finished product, the rolling temperature of the austenite non-recrystallization area is between 850 and 950 DEG C, and the final rolling temperature is between 800 and 900 DEG C; and after rolling, laminar cooling is performed, the final cooling temperature is between 650 and 750 DEG C, and the cooling rate is 5 to 15 DEG C per second. The thermal treatment process is characterized in that: the normalizing temperature is between 850 and 950 DEG C, and the heating speed is controlled at 1 to 1.5 minutes per millimeter. The method has the advantages of high yield, simple production process, short flow and short delivery time; and the ultra-thick plate has the following comprehensive properties that: the yield strength sigma s is 300 to 360MPa, the tensile strength sigma b is 500 to 550 MPa, the percentage elongation delta after fracture is more than or equal to 26 percent, the impact power AKv at 40 DEG C below zero is more than or equal to 100J, the cold bending property is qualified, and the mean value of the Z-directional section shrinkage is more than or equal to 25 percent.