OBJECTIVE：To investigate the application of clindamycin phosphate for inpatients in a third grade class A hospital， and provide reference for the specication of its application. METHODS： Retrospective investigation was adopted to randomly obtain the medical information of inpatients who used Clindamycin phosphate for injection in a third grade class A hospital in May 2014， and its rationality was evaluated and analyzed by referred the instructions， relevant provisions and principles. RESULTS： Totally 205 patients used Clindamycin phosphate for injection， among which 174 were for the purpose of prevention medicine， 31 cases for treatment purposes. There were reasonable use of 130 cases （63.4％）； unreasonable prophylaxis of 71 cases （34.6％）， unreasonable treatment of 4 cases （2.0％）， it was mainly no indication of medicine， usage and dosage， treatment course and use of antibacterial drugs. CONCLUSIONS： There still remains unreasonable phenomenon in the clinical application of the Clindamycin phosphate for injection， the safe and effective clinical application can only be ensured if the drug regulatory system is improved and antibacterial drugs in clinical medicine guidelines is strictly enforced.