NOVELTY - Preparing multi-element organic fertilizer by fermenting active humic acid naturally comprises (i) preparing active humic acid by taking humic acid raw materials, adding inorganic acid, filtering, adding alkali solution to the filtered materials; (ii) preparing a fermentation substrate by adding fresh animal bones to the active humic acid, crushing, and sieving; (iii) preparing a leaven by adding waste of animals and plants; (iv) adding industrial solid waste into the leaven, and crushing; and (v) taking fermentation substrate, leaven mixture and mineral substances, adding water and stacking.    USE - The active humic acid multi-element organic fertilizer prepared is useful for improving soil, increasing the soil fertility and improving the qualities of crops.    ADVANTAGE - The method: makes use of natural raw materials, comprising humic acid and fermented active potassium humic prepared from industrial solid waste, hence the product is utilized as a fertilizer, or product can be mixed with other nutrients and organic fertilizers for preparing high-quality microbial organic fertilizers and organic-inorganic fertilizer composition required by the crops; converts waste material into valuable fertilizer materials; and saves time and labor, hence the method is suitable for rural areas; and is environmental friendly, simple and convenient, and suitable for positive cycle of ecological organic agriculture.    DETAILED DESCRIPTION - Preparing multi-element organic fertilizer by fermenting active humic acid naturally comprises (i) preparing an active humic acid by taking humic acid raw materials, adding an inorganic acid, uniformly stirring for reacting, filtering, then adding an alkali solution into the filtered materials, and regulating the pH; (ii) preparing a fermentation substrate by adding fresh animal bones to the active humic acid, mixing according to the ratio of (90-98):(10-2) by weight, crushing, uniformly stirring, and sieving; (iii) preparing a leaven by adding waste of animals and plants, uniformly mixing according to a random ratio by weight; (iv) adding industrial solid waste into the leaven as the source of mineral substances, mixing according to the ratio of (70-90):(30-10) by weight of the leaven and the mineral substances, crushing, adding water and uniformly stirring; and (v) taking the fermentation substrate and the mixture of the leaven and the mineral substances according to the ratio of (50-80):(10-40) by weight, mixing, crushing, adding water and uniformly stirring, stacking for fermenting, rising the temperature to 80 degrees C from room temperature, continuing stacking for 25-35 days, and then cooling to room temperature to obtain the multi-element organic fertilizer.