The invention relates to a heat treatment method capable of improving an elongation rate of a PCRni3MOVA material forge piece. The method comprises the following steps that normalizing is conducted toheat to 610-650 DEG C firstly, then heating up to 880-900 DEG C is conducted, then heat preservation is conducted, and cooling to a room temperature is conducted; quenching is conducted to heat to 610-650 DEG C firstly, then heating up to 860-880 DEG C is conducted, the heat preservation is conducted, cooling and quenching are conducted, taking out of a furnace is conducted, and water cooling, air cooling, secondary water cooling and oil cooling are conducted for cooling and quenching; tempering at a high temperature is conducted to heat to 320-350 DEG C firstly, then preserving heat is conducted, and then heating up to 580-610 DEG C is conducted; after the furnace cooling to 400 DEG C is conducted, and taking out of the furnace is conducted for the air cooling. According to the method, the heat treatment mode of normalizing, cooling and quenching and high-temperature tempering is adopted, the material forge piece with a effective section phi 101 mm to phi 250 mm can be subjected to heat treatment, the elongation rate of the material forge piece subjected to the heat treatment can reach 16%-19%, technical requirements of an ultra-high pressure container forge piece can be met, andthe production process is high in operability.