Abstract: The effects of different cold rolling rate on the microstructure and mechanical properties of C17410beryllium-cobalt-copper alloy hot rolled strip blank during cold rolling were studied. And the cold working deformation mechanism of the alloy was analyzed. The results show that after 20% cold rolling of hot rolled strip, a large number of dispersed dislocations, dislocation cells and dislocation bands are produced in the alloy crystal, and the processing hardening effect is significant, which makes the strength and hardness of the alloy increase obviously and the elongation decreases sharply. When the processing rate is 40%, the number of dislocation cells increases, and twin crystals interact with dislocation and dislocation cells, so that the hardness and tensile strength continue to increase, and the elongation significantly decreases.When the processing rate increases to 60%, more fiber bands are formed in the alloy. When the processing rate is more than80%, the dislocation density increases and more shear bands are formed, which makes the grain obviously refined. After cold rolling, the tensile strength and hardness of the material increase from 347 MPa and 121HV in hot rolling state to 631 MPa and211HV in cold rolled processing rate of 95%, and the elongation decreases from 36.1% to 7.4%.