The invention discloses a water quality conditioner (ferment for conditioning water quality) added with a compound microorganism bacterium agent (enzyme microorganism). The water quality conditioner is prepared by fermentation of the following substances: zeolite, medical stones, an albumen powder, the compound microorganism bacterium agent, enzyme microorganism, amino acid and bone meal; a preparation method of the water quality conditioner is further provided, which is suitable for seawater and fresh water surface aquatic water bodies for breeding fishes, shrimps, crabs, shellfishes, turtles and eels and the like, and has the benefits as follows: the water quality conditioner prepared by adopting the preparation method can quickly act on bottom mud, so that ammonia nitrogen, hydrogen sulfide and nitrite are reduced, and the PH value is stabilized; the photosynthetic ability is improved, the water color is regulated, and the water quality is improved; heavy metal ions are flocculated and adsorbed, and chemical materials and toxic components in pesticide are degraded; the looseness and air permeability of bottom mud can be improved, and the growth and breeding of algae are promoted; oxygen is supplied in a slow release manner, and the aerobic effect is better; the bottom mud environment is built, effective microbial communities are nourished and activated, peculiar smell and odor are disorganized and transformed quickly with the aid of the absolute advantage of probiotics, and an excellent ecological environment can be provided for aquaculture animals.