Abstract: The cold deformation work hardening characteristics of BAl7-7-2-2 copper alloy are investigated by compression test at room temperature. The results show that the modified Ludwik model can accurately fit the true stress-true strain data of BAl7-7-2-2 copper alloy. The relevant material constants K=1 001.736, M=0.295 and n=0.044, and the correlation coefficient of fitting equation can reach 0.96. The work hardening rate is very high and increases rapidly when the true strain ε<0.02. When 0.02 ≤ ε ≤ 0.2, the stress continues to increase with the increase of strain, and the work hardening rate gradually decreases. When ε>0.2, the work hardening rate tends to be constant with the increase of strain, and the stage is weak hardening. The results of microstructure and hardness test show that the deformation mechanism of the material is different at different deformation stages.