A heat-treatment technology of a high-plasticity nickel base alloy comprises following steps: firstly, the temperature of the alloy rises, then, low-temperature solid-solution treatment is carried out, and after the alloy keeps warm for a certain period, air cooling is carried out; two-stage low-temperature aging is carried out; and the technical problems that the alloy is poor in plasticity and too long in heat treatment duration are solved. The strength of the alloy prepared through the method is slightly improved, the plasticity is obviously improved, the rising amplitude reaches 30 % to 35%, the heat treatment duration is one half of the original heat treatment duration, and the heat treatment time is greatly shortened.