The invention discloses a fermented Chinese herbal 
medicine additive for increasing yield of 
oyster seedlings. The fermented Chinese herbal 
medicine additive is prepared from the following raw materials (by weight): 6-12% of 
gynostemma pentaphylla, 3-5% of 
coptis, 4-8% of 
Hizikia fusiforme, 4-8% of 
milk thistle, 5-10% of sweet wormwood, 6-12% of magnolia cortex, 10-15% of purslane, 4-8% of 
dandelion, 6-15% of epimeddium, 8-15% of 
isatis root, 5-10% of cordate 
houttuynia, 5-10% of perilla leaf and 4-8% of 
plantago. The invention also discloses a preparation and application method of the fermented Chinese herbal 
medicine additive for increasing yield of 
oyster seedlings. The Chinese herbal medicinal 
raw material sources are wide, the cost is low, and the production 
processing technology is simple. By ultrasonic-assisted extraction and then by aerobic 
fermentation and anaerobic 
fermentation, functional components and beneficial microbial components of the Chinese herbal medicine are enhanced. The product has effects of improving water for growing 
oyster seedlings, effectively inhibiting 
outbreak of 
disease microbes, enhancing 
immunity and 
disease resistance of oyster seedlings and raising 
survival rate of seedlings. The product is an ideal, green, environment-friendly, safe and novel Chinese herbal medicine additive.