Objective To analyze the potential factors facilitating post-pyloric placement of spiral naso-jejunum tube in critically ill patients.Methods A retrospective study was carried out in patients requiring enteral nutrition (EN) from Apr 2005 through Dec 2011 in Intensive Care Unit (ICU).Severity of illness was assessed with APACHE Ⅱ score (acute physiology and chronic health evaluation Ⅱ).A selfpropelled spiral naso-jejunum tube was placed and observed for 24 hours.The forward movement and place of the tube tip was checked by bedside X-ray.The APACHE Ⅱ score,therapeutic measures,agents administered within 24 hours after tube insertion were recorded.The patients were divided into the success group and the failure group identified by bedside X-ray whether the tube tip entered into jejunum or not.Univariate analysis and multivariate Logistic regression analysis were used to find out the potential factors impacting on the success or failure in post-pyloric placement of naso-jejunum tube.Results A total of 508 patients composed of 337 male and 171 female,and aged (62.0 ± 19.2) years with APACHE Ⅱ score of (21.9 ± 7.3) were enrolled for study.The placement was successful in 205 (40.4％) of 508 patients.Univariate analysis showed that APACHE Ⅱ score ≥ 20,sedatives and analgesics,catecholamines,prokinetics,artificial airway and mechanical ventilation were potential factors facilitating the post-pyloric placement of naso-jejunum tube.Multivariate logistic regression identified that APACHE Ⅱ score ≥ 20,sedatives and analgesics and prokinetics were independent factors facilitating the post-pyloric placement of naso-jejunum tube.Conclusions The success rate of self-propelled spiral nasojejunal tubes insertion was relatively low.The prokinetics contributed higher success rate of naso-jejunum tube placement than factors of APACHE Ⅱ score ≥ 20,sedative and analgesic,catecholamine drugs,artificial airway and mechanical ventilation.There were no effects of age and gender on the placement of naso-jejunum tube.