DDisclosed are levocarrimycin pharmaceutical compositions preparation methods and uses thereof. Levocarrimycin is a mixture of isovalerylspiramycin III II and I as main components and contains certain content of isobutyrylspiramycin III and II butyrylspiramycin III and II propionylspiramycin III and II as well as acetylspiramycin III and II wherein the content of isovalerylspiramycin III is not less than 30 wt% the total content of isovalerylspiramycin III II and I is not less than 60 wt% and the content of acylspiramycin is 80 98 wt%. Specific optical rotation of said levocarrimycin is [a] = 52° ~ 57° in the solution of 0.02g/ml chloroform at temperature of 25°C. Also disclosed are levocarrimycin comprising the crystal of isovalerylspiramycin III II or I and pharmaceutical compositions containing said levocarrimycin. The active components in levocarrimycin or its pharmaceutical compositions has optical activity and excellent anti infective effect.
