The invention provides a ready-to-use 
adjuvant of 
livestock vaccines, preparation and applications thereof, belonging to the field of the 
adjuvant of 
livestock vaccines. The ready-to-use 
adjuvant is prepared from the following substances: 5-30 percent of oil, 0.1-10 percent of hydrophilic surfactant, 0.1-10 percent of oleophilic surfactant, 0.1-10 percent of polymeric 
micelle substance and 40-90 percent of water. The invention also provides a preparation method of the ready-to-use adjuvant, and the method comprises the following steps: respectively weighing the substances, mixing and then emulsifying, and degerming to obtain the ready-to-use adjuvant of the 
livestock vaccines. The invention also provides an oil-in-water 
type vaccine with the ready-to-use adjuvant. The ready-to-use adjuvant is an oil-in-water type adjuvant and has the advantages of simple ingredients, stable 
dosage form, convenience in use and easiness in injection. The preparation method of the ready-to-use adjuvant has a simple process and is low in cost, and the obtained 
dosage form is stable. The oil-in-water 
type vaccine has the advantages of long stable period, easiness in storage, good immune effect, protection period prolonging, easiness in injection and small 
side reaction.