The invention discloses a holothurian culture 
water quality restoration agent for effectively removing water 
eutrophication and a preparation method and application of the holothurian culture 
water quality restoration agent, belonging to the technical field of 
aquaculture and marine microorganisms. Aiming at the physiological 
habit and culture characteristic of holothurian, a marine 
microorganism technology is applied, the restoration agent consists of 
bacillus flexus CGMCC No.5115, 
bacillus subtilis CGMCC No.5116 and 
bacillus cereus CGMCC No.5117 separated and screened from a holothurian 
culture environment, 
corn meal and 
soya bean meal serving as major culture raw materials are fermented at the temperature of 28-37 DEG C for 24-48 hours, and attapulgite, medical stone and rice 
hull serving as adsorption and suspension composite carriers are used for 
processing to obtain the holothurian culture 
water quality restoration agent for effectively removing water 
eutrophication. The product can adsorb harmful substances such as heavy ions including Hg<2+>, Pb<2+>, Cr<6+>, Cd<2+>, and Cu<2+> in water bodies, and the content of harmful substances such as 
ammonia nitrogen, 
nitrite, and 
hydrogen sulfide can be greatly reduced. Bottom 
odor and acidification of water bodies are avoided, pathogenic microorganisms are inhibited effectively, holothurian diseases are prevented, and the holothurian culture yield and quality are improved.