The influence of warm-rolling and annealing temperature on the microstructure and mechanical properties of ductile non-equal molar Co40Cr25Fe10Ni25 high entropy alloys (HEM) were investigated. The results indicate partial recrystallization occurs after annealing at 600 degrees C, heterogeneous grain structures are obtained after annealing at 700 degrees C, and complete recrystallization and grain growth occur at 900 degrees C. The different combination of ultimate tensile strength (830-1400 MPa) and ductility (10-70%) of Co40Cr25Fe10Ni25 HEAs were obtained, which is related to the microstructure after the rolling and annealing process. The heterogeneous grain structure leads to form the elongate voids during tensile deformation, owing to the local stress concentration in the especial structure.