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 sigmab 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.