The invention discloses a clostridium welchii bacteriophage as well as a bacteriophage composition and application thereof, the bacteriophage is a clostridium welchii bacteriophage PMQ06 and is preserved in China General Microbiological Culture Collection Center on May 15, 2020, and the preservation number is CGMCC No.19977. The bacteriophage has the advantages of high-efficiency bactericidal activity, wide lysis spectrum and high temperature stability, can be used as an active ingredient for preparing drugs for preventing and treating chicken clostridium welchii disease, environmental disinfectants, feed additives, bacteriostats and the like, can be widely applied to various links in the breeding process and the product processing and production process, and has broad market prospects. The pathogenicity clostridium welchii and even the drug-resistant clostridium welchii are rapidly, efficiently and safely killed, the mortality rate of morbidity chickens is effectively reduced, and thefeed additive has the advantages of being safe, free of residues and free of side effects.