The invention relates to a Chinese herbal medicine ultra-fine powder feed additive with antiviral and antibacterial effects, and a preparation method of the Chinese herbal medicine ultra-fine powder feed additive. The composition is prepared by pogostemon cablin, fructus forsythiae, radix isatidis, liquorice, honeysuckle, radix bupleuri and houttuynia cordata according to a certain proportion. The method comprises the steps of: firstly, respectively cutting the pogostemon cablin, the fructus forsythiae, the radix isatidis, the liquorice, the honeysuckle, the radix bupleuri and the houttuynia cordata into pieces; secondly, respectively grinding the pogostemon cablin, the fructus forsythiae, the radix isatidis, the liquorice, the honeysuckle, the radix bupleuri and the houttuynia cordata which are cut into pieces; thirdly, taking the the pogostemon cablin, the fructus forsythiae, the radix isatidis, the liquorice, the honeysuckle, the radix bupleuri and the houttuynia cordata according to a certain proportion, and fully mixing; and fourthly, further carrying out superfine grinding treatment on the mixture to enable the average particle size to be 30mu m, split charging, sealing and storing. The Chinese herbal medicine ultra-fine powder feed additive is reasonable in formulation, definite in effect, free from toxic and side effects, complete in release of effective components, rapid in effect, easy in implementation of method, and suitable for large-scale production. The Chinese herbal medicine ultra-fine powder feed additive has the antiviral, antibacterial and anti-inflammation effects, improves the intestinal tract environment, improves the immunity of the organism and the disease resistance, and improves the growth performance.