Objective To study the risk factors and pathogenesis of pulmonary infection in acute stroke patients. Methods A retrospective analysis was taken in 257 acute stroke cases to investigate the incidence of pulmonary infection and its relationship with the underlying disease, disturbance of consciousness, invasive operation,the type of pathogenic bacteria and drug susceptibility. Results The positive rate of pulmonary infection in acute stroke patients was high and related to many factors including severity of stroke, disturbance of consciousness,primary diseases, and invasive examination etc. The most popular infective bacteria were Gram-negative bacteria. The imipenem was most sensitive to Gram-negative and Gram-positive bacteria, followed by Amikacin and piperacillin too. Conclusions The pulmonary infection in cerebral stroke patients is caused by many factors, of which Gramnegative bacteria play the most important role. Identification of the risk factor and pathogenic bacteria is helpful in treating cerebral stroke infectious complications.