The work aims to study the corrosion behavior of mold on PCB-Cu in tropical forest environment. Two fungi strains with the most high occurrence frequency, Fusarium solani and Daldinia eschscholtzii were selected from surfaces of PCBs via PDA culture . The dry weight method was used to study the effect of Cu2+ on biological activity. The biofilms on surface of PCB-Cu were observed by SEM and the polarization curves were adopted to investigate the electrochemical corrosion behavior. After 6 days, both fungi strains could form biofilm on PCB-Cu surface and accumulate corrosive products at mycelium concentration. At the same time, the increase of Cu2+ concentration in thin liquid membrane could inhibit the growth of bacteria. Compared with aseptic group, both strains could inhibit the increase of PCB-Cu self-corrosive potential Ecorr in the early stage and the decrease of PCB-Cu self-corrosive potential Ecorr in the later stage. After inoculation of fungal spores on PCB-Cu surface, the activity of fungi is better because the content of Cu2+ in the thin liquid film on PCB-Cu surface is lower in the initial stage, and the secretion inhibits the formation of oxide film on PCB-Cu surface, thus promoting the corrosion of PCB-Cu in the initial stage. However, with the corrosion reaction proceeding, the concentration of Cu2+ in the thin liquid film on PCB-Cu surface gradually increases, and the viability of fungi is inhibited, so the content of corrosive secretion decreases. At this time, the biofilm adhering to PCB-Cu surface protects the matrix and begins to inhibit corrosion.