Using anti-Pseudomonas PsI and PcrV binding molecules and related compositions in prevention and treatment of Pseudomonas infection are disclosed. Further provided are isolated binding molecules which specifically bind to Pseudomonas PcrV or Pseudomonas PsI, and bispecific antibodies that specifically bind to Pseudomonas PcrV and Pseudomonas PsI. The sequences of heavy chain and light chain as well as sequences of complementarity determining regions (CDRs) of these binding molecules are further disclosed.