Objective: To isolate murine anti endotoxin single chain phage antibody from a constructed library. Methods: Total RNA was firstly extracted from murine splenic cells and mRNA was reverse-transcribed into cDNA. Then the designed primers were used to amplify the variable region genes of the heavy and light chain (VH, VL) with polymerase chain reaction. The linker was used to assemble the VH and VL into ScFv, and the NotI and SfiI restriction enzymes were used to digest the ScFv in order to ligate into the pCANTAB5E phagemid vector that was already digested with the same restriction enzymes. The ligated vector was then introduced into competent E.coli TG1 cells to construct a single-chain phage antibody library. After rescued with M13KO7 helper phage, recombinant phages displaying ScFv fragments were harvested from the supernatant and selected with endotoxin. The enriched positive clones were reinfected into TG1 cells. Finally, 190 clones were randomly selected to detect the anti endotoxin antibody with indirect ELISA. Results: The titer of anti endotoxin in murine sera was 1:12,800. The concentration of total RNA was 12.38 mg/ml. 1.9107 clones were obtained after transformed into TG1. 3104 colonies were gotten after one round panning. Two positive colonies were confirmed with indirect ELISA among 190 randomly selected colonies. Conclusion: A 1.9107 murine anti endotoxin single chain phage antibody library was successfully constructed. Two anti endotoxin antibodies were obtained from the library. Objective: To isolate murine anti endotoxin single chain phage antibody from a constructed library. Methods: Total RNA was derived from murine splenic cells and mRNA was reverse-transcribed into cDNA. Then the designed primers were used to amplify the variable region genes of the The linker was used to assemble the VH and VL into ScFv, and the NotI and SfiI restriction enzymes were used to digest the ScFv in order to ligate into the pCANTAB5E phagemid vector that was originally digested with the same restriction enzymes. The ligated vector was then introduced into competent E. coli TG1 cells to construct a single-chain phage antibody library. After rescued with M13KO7 helper phage, recombinant phages displaying ScFv fragments were harvested from the supernatant and selected with endotoxin. The enriched positive clones were reinfected into TG1 cells. Finally, 190 clones were randomly selected to detect the anti endotox in antibody with indirect ELISA. Results: The titer of anti endotoxin in murine sera was 1: 12,800. The concentration of total RNA was 12.38 mg / ml. 1.9107 clones were obtained after transformed into TG1. 3104 colonies were gotten after one round panning. Two positive colonies were confirmed with indirect ELISA among 190 randomly selected colonies. Conclusion: A 1.9107 murine anti endotoxin single chain phage antibody library was successfully constructed. Two anti endotoxin antibodies were obtained from the library.