The invention relates a new active clindamycin phosphate compound and a medicinal composition of the compound. When the clindamycin phosphate compound is determined by using powder X-ray diffraction, characteristic diffraction peaks appear at the angels of 4.85 degrees, 5.73 degrees, 6.64 degrees, 9.12 degrees, 11.98 degrees, 13.51 degrees, 17.37 degrees, 19.61 degrees, 21.76 degrees, 22.23 degrees, 23.46 degrees, 26.82 degrees, 28.16 degrees, 33.68 degrees and 34.29 degrees in a X-ray diffraction pattern represented in 2theta +/-0.2 degree diffraction angles. The stability of the clindamycinphosphate compound provided by the invention is improved remarkably; the influences on the appearance, content and other aspects of the clindamycin phosphate compound caused by long-term storage can be ignored, thereby ensuring the drug safety for patients. In addition, the new clindamycin phosphate compound is suitable to be popularized and applied to various clindamycin phosphate preparations.