The invention relates to a novel crystal form of valnemulin hydrogen tartrate and a preparation method thereof. The method comprises the steps of dissolving valnemulin hydrogen tartrate with the purity being over 95% into a mixed solvent of an ester solvent and N,N-dimethylformamide, adding an elution agent after complete dissolution so as to carry out elution crystallization, then, cooling a solution to the temperature of 5-15 DEG C, and washing, filtrating and drying crystal slurry, thereby obtaining a valnemulin hydrogen tartrate product. An X-ray powder diffraction atlas of the crystal has characteristic peaks when a diffraction angle 2[theta] is equal to 2.5, 4.8, 7.4, 7.5, 10.1, 11.2, 11.7, 13.8 or 17.1 degrees. According to the novel crystal form, during crystallization, the yield reaches over 90%, the product purity reaches over 98%, the product is high in crystallinity, good in stability, difficult in moisture absorption and high in solubility, the water solubility at normal temperature reaches 6.5g/100mL and is increased by about 30% compared with that of the currently marketed products, and the water stability is good, so that the product can be conveniently prepared into a premix.