Abstract: Mo–30Cu alloy billets were prepared by powder metallurgy infiltration method, the rolled Mo–30Cu billets and oxygen-free copper plates were hot-pressed at 970 ℃ with a pressure of 30 MPa to obtain 5-layer Cu/MoCu/Cu (CPC) composites. The effects of the Mo–30Cu surface treatments on the interface bonding strength of the multi-layer CPC composites were studied by the microstructure observation, ultrasonic scanning analysis, high-temperature thermal examination, and air leakage rate testing. The results show that, the multi-layer CPC composites prepared by Mo–30Cu interlayer materials treated by wiredrawing have no cavity defects after being heated at 830 ℃ for 10 min, and the leakage rate is less than 5×10⁻³ Pa·cm³·s⁻¹. The multi-layer CPC composites prepared by Mo–30Cu interlayer materials treated by grinding show the bulging phenomenon after the thermal examination, have the obvious cavity defects in the interior, and the leakage rate is greater than 5×10⁻³ Pa·cm³·s⁻¹.