The invention discloses a multi-element water-soluble liquid fertilizer, which is prepared by the following raw materials: water, urea, dipotassium phosphate, disodium zinc ethylenediaminetetraacetate tetrahydrate, boric acid and citric acid in a certain weight percentage. The preparation method comprises the following steps: putting the raw materials into a reaction kettle, continuously stirring at a certain temperature and statically cooling to 15-20 DEG C; and then taking the stirred substance namely the multi-element water-soluble liquid fertilizer out of the reaction kettle. The liquid fertilizer is reasonable in ingredient and convenient to use; the preparation method is simple and easy to operate; fertilization can be performed along with water irrigation; not only water but also the fertilizer is saved; moreover, the labor is saved and cleanness is achieved. The fertilizer causes no pollution to the environment, is low in cost, convenient to use and capable of being directly absorbed by plants without transformation by soil, is used for satisfying the requirements of the plants on nutrient elements, produces effects of growth promotion, rooting, seedling strengthening, flower formation promotion, fruit retention, disease prevention, stress resistance, production increment and quality improvement, and is colorless and tasteless, and widely applied to the fields of agriculture, forestry and the like.