The pharmaceutical composition of injectable, the method and preparaton used are disclosed. The composition includes: one or more water-soluble compounds, and each complex includes cyclodextrin or cyclodextrine derivatives and a kind of dewatering medicament At least one preservative With at least one cosolvent. The composition effectively saves the preservation of Te Site antimicrobial efficacies according to European Pharmacopoeia 2011, at least meet B criterion, because it be applied to it is parenteral, instruct antibacterial efficacy to test with United States Pharmacopeia 2011, meet criterion classification 1 (injection) product.