The invention discloses a liquid water-soluble fertilizer containing humic acid and a preparation method of the liquid water-soluble fertilizer. The liquid water-soluble fertilizer is prepared from the following materials in parts by weight: 8-13 parts of a urea ammonium nitrate solution, 8-14 parts of ammonium polyphosphate, 14-20 parts of potassium tripolyphosphate, 7-11 parts of mineral sourcepotassium fulvic acid, 1-3 parts of a non-ionic surfactant, 0.05-0.2 part of endophyte source extract cyclodipeptides, 0.1-0.3 part of an organic silicon defoamer, 0.2-0.6 part of IDHA iron, 0.1-0.5 part of glycerol, 0.1-0.5 part of xanthan gum and 36.9-61.45 parts of water. The preparation method comprises the following steps that the xanthan gum is added into the 6 parts of water in a reaction kettle, uniform stirring is conducted, still standing is conducted for 24 h, then the residual water, the potassium fulvic acid, the surfactant and the defoamer are added, heating is conducted to 50 DEG C, and stirring is conducted for 5 min; the urea ammonium nitrate solution, the ammonium polyphosphate, the potassium tripolyphosphate, the IDHA iron and the like are added into a solution, the cyclodipeptides and the glycerol are added after complete dissolving, heating is conducted to 50 DEG C, stirring is conducted for 5 min, cooling is conducted to the room temperature, and thus packaging can be conducted. The liquid water-soluble fertilizer is simple in process, a product meets the requirements of current drip irrigation equipment, the use effect is good, and the liquid water-soluble fertilizer can be widely popularized.