The interlaminar fracture toughness of aluminum alloy/carbon fiber reinforced plastic (CFRP) joints subjected to accelerated aging due to corrosion was investigated over time. An acoustic emission (AE) measurement was performed as an evaluation method in conjunction with double cantilever beam testing. It was confirmed that the difference in the number of cross-linking points in the adhesive affected the fracture morphology and corrosion behavior, which resulted in a change in the fracture toughness. The AE measurements facilitated the visualization of the process zone and real-time monitoring of the fracture morphology, and they were able to capture changes in the fracture behavior with the corrosion progression.