The invention discloses a water soluble fertilizer and a production method thereof, in particular to a water soluble humic acid multi-element solid fertilizer and a production method thereof. The water soluble humic acid multi-element solid fertilizer is made by mixing water soluble humic acid, water soluble nitrogenous fertilizer, water soluble phosphorous fertilizer, water soluble potassic fertilizer and water soluble complex trace elements. Compared with the prior art, the water soluble humic acid multi-element solid fertilizer can reduce the transporting and packing cost, can be rapidly dissolved without agglomeration when in use, is applied along with water, and has the advantages of strong points, high nutrient content, complete nutrition, good water-solubility, combination of organic and inorganic matters as well as high effect of fertilizer and utilization rate. The utilization rate of product nitrogen reaches 60%, the utilization rate of phosphorus is 30-35%, and the utilization rate of potassium is 60-70%, so that the fertilizer application utilization rate is increased by more than 10% compared with the conventional fertilizer.