The invention provides a disinfectant with low corrosiveness. The disinfectant comprises the following components by weight percent: 0.2-2.0% of ortho-phthalaldehyde, 1-10% of a synergist, 10-50% of a cosolvent, 0.5-5% of a buffering agent, 1-10% of a penetrant, 0.2-2% of a corrosion inhibitor, 0.1-5% of a chelating agent, 0.1-3% of a stabilizing agent and 45-80% of purified water. After the disinfectant is used, intestinal tract pathogenic bacteria, pyogenic coccus, hepatitis virus, H7N9 avian influenza virus, black variant spores of bacillus subtilis and other pathogenic microorganisms can be killed within a short time. Furthermore, the disinfectant adopts a slow release technique, thus having extremely low corrosiveness on metal and being very suitable for disinfecting medical equipment.