The invention relates to a nasal spraying agent of thymopentin, and a preparation method and applications thereof. The preparation is used in over18-year-old sufferers of chronic hepatitis B, various primary or secondary defect diseases of T cellular, certain autoimmune diseases, various diseases of low cellular immune function and adjutant therapy to tumours; the preparation consists of thymopentin, pharmaceutic adjuvant and water; the preparation method of the agent includes the steps of liquid preparation, degerming, split charging, stoppering, capping, package, etc. The medicament form overcomes the difficulty that polypeptide drugs are unsteady in water, thus keeping the activity of thymopentin well and having good stability; meanwhile, pain is not produced when the medicament form is used, thus being accepted by the general consumers.