The invention discloses a disinfectant used for breaking a bacterial biofilm. The disinfectant is prepared from components in parts by weight as follows: 0.5-3 parts of phenyllactic acid and 1 part of lactic acid. The disinfectant used for breaking the bacterial biofilm can effectively break the bacterial biofilm through the synergistic effect of phenyllactic acid and lactic acid and contains simple components, the concentration of disinfection components is low, the use effect of the disinfectant can be improved, the dosage of the disinfectant is reduced, and harm to the environment and human bodies is reduced.