Ｏｂｊｅｃｔｉｖｅ　To compare therapeutic values of intravenous infusion and inhalation of penehyclidine hydrochloride in the treatment of large volume lung lavage.　Methods　Forty patients with large volume lung lavage were randomly divided into two groups, receiving penehyclidine hydrochloride 0.01 mg/kg through either intravenous infusion (group A) or inhalation (group B). Respiratory dynamics was evaluated by recording peak airway pressure (Ppeak) and lung dynamic compliance (Cdyn) after intubation (T0), before irrigation (T1), by the end of irrigation (T2), and 30 min (T3), 60 min (T4), 90 min (T5), 120 min (T6) after the irrigation. Additional information acquired included the total amount of the lavage fluid, the residual volume of the irrigation fluid, the time of the irrigation and the collection of the oral secretions.　Results　Compared with the levels at T0, in both groups, Cdyn was significantly increased, but Ppeak was significantly decreased. At T4, T5, compared with group A, group B showed increased Cdyn, but decreased Ppeak.　Conclusions　Preoperative inhalation of penehyclidine hydrochloric is beneficial to postoperative recovery in patients receiving large volume lung lavage. It can improve ventilation, and accelerate the recovery of respiratory function.