The invention relates to a treatment medicament for resisting infectious diseases, and a preparation method and application thereof, in particular to an alkyl acyl acetaldehyde sulfite derivative and a preparation method and application thereof. The derivative has the high storage stability, and is suitable for preparing medicaments for treating or preventing respiratory tract infection of human or animals, urogenital system infection, gastrointestinal tract bacterial infection, the infection of enterocoelia, pelvic cavity, biliary tract and typhia, injection of bones and joints, skin soft tissue infection, septicemia, cervicitis, sinusitis, tympanitis, blepharitis, conjunctivitis and psoriasis which are caused by Gram-positive or negative bacterial sensitive bacteria, virus, chlamydia, mycoplasma and fungi and liver cancers and enhancing immunity.