The invention discloses an LAMP (Loop-Mediated Isothermal Amplification) primer used for detecting infectious haematopoietic necrosis virus and application thereof. The primer disclosed by the invention is a primer group, wherein the primer group consists of a primer 1, a primer 2, a primer 3, a primer 4, a primer 5 and a primer 6; or the primer group consists of the primer 1, the primer 2, the primer 3 and the primer 4; nucleotide sequences of the primer 1, the primer 2, the primer 3, the primer 4, the primer 5 and the primer 6 are respectively expressed as a sequence 1, a sequence 2, a sequence 3, a sequence 4, a sequence 5 and a sequence 6 in a sequence table. Due to the adoption of the primers, an IHNV RT-LAMP (Infectious Haematopoietic Necrosis Virus Reverse Transcription Loop-Mediated Isothermal Amplification) visual detection method is established by adding SYBR Green I fluorescent dye into a reaction solution; meanwhile, according to the method, the sensitivity is high, the specificity is good, the cost is low and field high-flux fast detection can be realized without depending on any special instrument equipment, so that an important significance isi provided for introduction of trout fries, breeding of fishes without special pathogen type and pollution-free cultivation of trout.