Objective: To study the effect of BRL-37344 on alveolar fluid clearance (AFC) in isolated human lung and the mechanisms involved. Methods: Isomolar albumin solution in the presence of 10-4mol/L to 10-8mol/L BRL-37344 (selective β3-adrenergic agonists) was injected into the alveolar spaces in isolated human lung, and AFC was measured. 10-5mol/L BRL-37344 combined with phentolamine (α receptor antagonist), atenolol (β1 receptor antagonist), ICI-118551 (β2 receptor antagonist), SR59230A(β3 receptor antagonist), sodium channel blockers or Na /K _ ATPase blockers were perfused into the alveolar space of isolated human lung. Results: 10-4mol/L to 10-7mol/L BRL-37344 increased AFC significantly in isolated human lung，but 10-8mol/L BRL-37344 can not increase AFC. The AFC-stiulating effect of BRL-37344 was lower with SR59230A, amiloride and ouabain. Conclusion: BRL-37344, aβ3-adrenergic agonist, can increase AFC in isolated human lung through promoting the transport of Na -K -ATPase and accelerate the amelioration of pulmory edema.