Hot compression experiments on the supersaturated nickel-based superalloy GH4742 were conducted using a MTS793 testing machine, covering a temperature range from 1000 ℃ to 1150 ℃ and strain rates from 0.001 s−1 to 1 s−1. A cubic polynomial was employed to describe the relationship between \(ln\sigma \) and \(ln\dot{\varepsilon }\) in order to accurately calculate strain rate sensitivity index ( \(m\) ) values. Higher \(m\) values at γ′ super-solvus temperatures indicated better workability. The processing map of the supersaturated GH4742 alloy at terminated strain was successfully constructed based on the dynamic material model (DMM) and Prasad instability criterion. The results indicated that power dissipation efficiency ( \(\eta \) ) values exhibited a distribution trend similar to the \(m\) values. The instability zone was small and mainly concentrated at lower deformation temperatures, demonstrating the good hot workability of the GH4742 alloy in its supersaturated state. This work confirms the feasibility of dissolving γ′ precipitates to enhance hot working capabilities of the GH4742 alloy, providing guidance for other highly alloyed wrought nickel-based superalloys strengthened by γ′ precipitates.