OBJECTIVE To explore the effect of high volume hemofiltration (HVHF) on pulmonary surfactant protein (SP) in endotoxin induced acute lung injury (ALI) in dogs. METHODS Sixteen healthy male mongrel dogs were given lipopolysaccharide(LPS 650 mug/kg) via central vein within 30 minutes. After the reproduction of the model, they were divided into two groups randomly (n=8). One group received the treatment of HVHF and mechanical ventilation (MV, treatment group), while another received only MV (model group). Parameters of arterial blood gas and respiratory mechanics were recorded at basic values, after reproduction of the experimental model, and 1, 2 and 4 hours after HVHF. Content of SP-B in lung tissue homogenate was measured by protein Western blot. RESULTS After injection of LPS, partial pressure of oxygen in artery (PaO(2)) and PaO(2)/fractional concentration of inspired oxygen (FiO(2)) began to decrease (both P<0.05). PaO(2)/FiO(2) <300 mm Hg (1 mm Hg=0.133 kPa) when ALI was reproduced. PaO(2) and PaO(2)/FiO(2) were higher in treatment group than those in model group 4 hours after HVHF (both P<0.01). Inspiratory resistance of airway (Raw) and peak inspiratory pressure (PIP) in model group were kept stable after MV. Lung dynamic compliance (Cdyn) and lung total compliance (Ctot) in model group were both decreased while ventilatory work of breathing (WOBvent) increased 4 hours after MV (all P<0.01). All parameters in the treatment group were kept stable and differences in Cdyn and Ctot were significant at 4 hours after HVHF compared to model group (P<0.01 and P<0.05). Content of SP-B in lung tissue homogenate was significantly higher in treatment group than that in model group (P<0.01). CONCLUSIONS HVHF could effectively increase the content of SP-B in lung to prevent aggravation of respiratory mechanics and improve oxygenation.