NOVELTY - Preparing valnemulin hydrochloride, comprises: reacting pleuromutilin and p-toluenesulfonyl chloride to prepare pleuromutilin-22-O-sulfonate, and adding dimethyl-cysteinyl hydrochloride to the pleuromutilin-22-O-sulfonate to prepare thioether; preparing D-valine dane salt by reacting D-valine, acetoacetate and an alkali, adding a dispersant to the mixture and then stirring and filtering; and reacting D-valine dane salt with chloroformate, adding thioether to the mixture and then heating and hydrolyzing to give a crude valnemulin hydrochloride solution and then purifying.    USE - The method is useful for preparing valnemulin hydrochloride (claimed).    ADVANTAGE - The method allows simple, safe and economical preparation of the valnemulin hydrochloride with less labor intensity, high yield and reduced pollution.    DETAILED DESCRIPTION - Preparing valnemulin hydrochloride, comprises: (1) reacting pleuromutilin and p-toluenesulfonyl chloride in the presence of a solvent A under alkaline conditions at a temperature of 30-60 degrees C for 1-2 hours to prepare pleuromutilin-22-O-sulfonate, and adding dimethyl-cysteinyl hydrochloride to the pleuromutilin-22-O-sulfonate in the presence of a phase transfer catalyst under basic conditions at a temperature of 35-60 degrees C for 1-3 hours to prepare thioether; (2) preparing D-valine dane salt by reacting D-valine, acetoacetate and an alkali in the presence of a solvent B at a temperature of 45-85 degrees C for 1-3 hours, evaporating dryness of the reacted mixture, adding a dispersant to the mixture and then stirring, and filtering the stirred mixture and then drying; (3) reacting D-valine dane salt with chloroformate in the presence of a solvent and then performing base-catalyzed reaction at a temperature of -10 degrees C to 5 degrees C for 1 hour, adding thioether obtained from the step (1) to the reacted mixture and then heating for 1-2 hours, and hydrolyzing the mixture under acidic conditions to give a crude valnemulin hydrochloride solution; (4) purifying the crude valnemulin hydrochloride solution, and removing salt content and solvent content from the purified solution using concentrated hydrochloric acid and then distilling.