The invention provides a compound EM active beneficial bacteria mother liquor bio-organic liquid fertilizer, which comprises main raw materials of seaweed, kelp, Ganoderma applanatum, Coprinus comatus, pollen, shoestring fungus, Gynostemma pentaphylla, spirulina, Hericium erinaceus, cicada fungus, saffron, Isaria cicadae Miquel, Ganoderma lucidum, and seaweed dietary fiber. The present invention also provides a preparation method of the organic liquid fertilizer and application thereof. The liquid fertilizer can effectively improve the crop root growth environment, promote the root growth, facilitate the absorption of mineral nutrition in soil by the roots, prevent aging of crops, improve yield and quality of the crops, and enhance the disease resistance of crops. For the aspect of poultry feed, due to the role of photosynthetic bacteria, the liquid fertilizer can eliminate odor of feces, and purify the sludge, wastewater and waste residues in pigpen, cattle pen and sheep pen, so that the liquid fertilizer produced from farming can reach the use standards, improve the nutritional effect of liquid fertilizer on plant, and prevent influenza in poultry.