TiO/Cu(OH)CO nanocomposite were synthesized via a simple in-situ precipitation process, which was applied as efficient antimicrobials for the inactivation of Escherichia coli (E. coli) and Fusarium graminearum (F. graminearum) under simulated solar light. With optimum Cu(OH)CO amount of 1.8 mol%, the TiO/Cu(OH)CO nanocomposite presented the highest antimicrobial activities against E. coli and F. graminearum, and achieved complete inactivation in 80 min, which was far better than that of bare TiO. The boosted photocatalytic disinfection efficiency was ascribed to the increased light harvesting and efficient charge transfer and separation in the TiO/Cu(OH)CO nanocomposite, which resulted in more efficient generation of •OH and •O that played important role in the photocatalytic inactivation process. Our work revealed that TiO/Cu(OH)CO composite was a promising antimicrobial agent for prevention of pathogenic fungal or bacterial infections in crop protection.