OBJECTIVE： To explore the mode and role of clinical pharmacists participating in pharmaceutical care of anti-infective therapy for patients with severe pulmonary infection. METHODS： Clinical pharmacists participated in diagnosis and treatment for a patient with severe pulmonary infection. The rationality of therapy regimen was evaluated， and therapeutic efficacy was also evaluated according to the change of relative index； clinical pharmacists assisted physicians to optimize therapy plan： suggest to stop taking moxifloxacin and give Meropenem for injection 1.0 g，ivgtt，q12 h for anti-infective therapy if getting worse； suggest to stop taking meropenem and give Levofloxacin hydrochloride injection 0.5 g，ivgtt，qd+Aztreonam for injection 2.0 g，ivgtt，q12 h according to sputum culture if infection controlled； suggest to stop taking levofloxacin and give vancomycin 1.0 g，ivgtt，q12 h after infection aggravated because MRSA infection can not be excluded； suggest to stop taking aztreonam and give Cefepime hydrochloride for injection 2.0 g，ivgtt，q12 h+Amikacin sulfate injection 0.4 g，ivgtt，qd，and blood concentration of vancomycin if pulmonary infection aggravated； suggest to stop taking vancomycin and continue to take cefepime+amikacin for anti-infective therapy due to MRSA was not found in sputum culture. RESULTS： Physicians adopted clinical pharmacist’ s suggestion； vital sign of patients become stable， and infection have been controlled significantly compared to before treatment； the patient was transferred to common ward. CONCLUSIONS： The participation of clinical pharmacists in the optimization of anti-infective therapy plan can improve efficacy， reduce ADR and avoid drug interaction.