The present invention provides a composition for preventing and treating sturgeon streptococcus disease, and an application of the composition, and belongs to the technical field of aquatic disease preventing and treating. The composition comprises the following components: an immune enhancer, vitamin C, Chinese rhubarb, radix scutellariae powder, lianjunjing (a veterinary medicine) and flufenicol. The composition is applied for sturgeon breeding, can enable survival rate of sturgeon suffering from streptococcus disease to reach 80%-90%, and can effectively prevent cross-infection in large-area culture. The composition is convenient to use, small in dosage, short in course of treatment, and good in curative effect, can effectively kill streptococcus iniae, has good disease control effectsof sicken fish, also enables the disease to be not liable to relapse, greatly improves survival rate of the sicken fish and reduces economic loss of farmers.