The invention relates to high-plasticity five-element refractory high-entropy alloy and a preparation method thereof and belongs to the field of metal materials. The high-entropy alloy is prepared from zirconium, titanium, hafnium, vanadium and niobium, wherein the molar weights of the zirconium, the titanium, the hafnium, the vanadium and the niobium are equal. The preparation method of the high-plasticity five-element refractory high-entropy alloy comprises the steps that the zirconium, the titanium, the hafnium, the vanadium and the niobium are placed in a water-cooling metal crucible in a melting point progressively-decreasing sequence, the element with the lowest melting point is placed at the bottom, and the element with the highest melting point is placed at the top; and arc striking smelting is conducted in an oxygen-free environment till the five elements are fully mixed, and the high-entropy alloy is obtained. The high-entropy alloy is of a single body-centered cubic structure, the yield strength of the high-entropy alloy is higher than 800 MPa, the tensile strength is over 1100 MPa, and the plastic strain is larger than 55%; and the large solid solubility between the elements is obtained, and a simple solid-solution phase is formed. The preparation method has the advantages that the power is high, the performance is table, operation is convenient, the melting point is high, the vacuum degree is high, and the quantity of impurities is small.