The invention belongs to the technical field of aluminum alloys and relates to a preparing technology for an O/H111 state 5454 aluminum alloy plate. The O/H111 state 5454 aluminum alloy plate includes, by mass percent, smaller than or equal to 0.15% of Si, smaller than or equal to 0.3% of Fe, smaller than 0.2% of Cu, 0.8%-1% of Mn, 2.8%-3.0% of Mg, 0.08%-0.12% of Cr, smaller than 0.1% of Zn, smaller than or equal to 0.025% of Ti, smaller than or equal to 0.05% of each of other impurities and the balance Al, wherein the total amount of other impurities is smaller than or equal to 0.15%. A castingot composed of the above components is subjected to heat preservation for 2 h to 3.5 h under the temperature of 500 DEG C, the temperature is reduced to 450 DEG C for heat preservation in the timezone, then the cast ingot is discharged out of a furnace to be rolled, and the hot rolling finishing rolling temperature is controlled to be larger than or equal to 320 DEG C. By means of the 5454 aluminum alloy plate prepared through the technology, the tensile strength of the 5454 aluminum alloy plate is larger than 250 MPa, the yield strength is larger than 130 MPa, and the elongation is largerthan 22%. By means of the machining technology, high-strength and high-elongation 5454-O/H111 state plates can be produced in a batched manner, and the safety of tank trucks in the use process can bebetter ensured due to the plates.