Objective To investigate the value of continuous blood purification （CBP）in early treatment of patients with ARDSexp （ARDS caused by extrapulmonary causes），especially in reducing inflammation mediators and extravascular lung water （EVLW）.Methods According the hospital admission sequence，the patients with APACHEⅡ scores from 15 to 20 and PaO2/FiO2 from 100 to 200 were recruited.The ARDSexp patients were divide into an intervention group treated with CBP （Mode：CVVHDF，rate of displacement liquid and dialysate：1.5 L/h，rate of blood：100-200 mL/h，and the time of CBP：72 hours），and a control group without CBP treatment. The NICO and PICCO monitoring data and the survival rates were recorded and analyzed using the SPSS software. Results The mortality rate of the intervention group was lower than that of the control group （6.3% vs. 36.8%，P=0.032）. In the 72 h monitoring dada of NICO and PICCO，the time of improving PCBF，Pm，Cdyn，VCO2，MValv，Pm，PIP，Raw，RSBI，Vd/Vt，and PaO2/FiO2 of the intervention group was severer than those in the control group，and the severety was also more than that of control group which was was significantly different at 72 h（Plt;0.05）. In the PICCO data，the time of decreasing EVWL and PVPI was shorter than the control group，and the decreasing extent was more than the control group，with significant difference at 72 h. But the changes of Apm，CI，and CVP were not significant （Pgt;0.05）. Conclusions In treatment of ARDSexp patients，CBP therapy can induce the PCBC and EVLW，improve pulmonary compliance and MValv，and reduce the mortality rate，while doesn’t influence heart function and the stability of circulation.