Objective To evaluate packing methods of paper-plastic bag for ethylene oxide(EO) sterilization of flexible endoscopes. Methods Two packing methods of paper-plastic bag were adopted (group A:each endoscope was rolled up to the size of 40 cm, then put into a 40 cm×60 cm×10 cm three-dimensional bag; group B:each endoscope from insertion part to manipulation part was vertically put into a 25 cm×185 cm paper-plastic bag), endoscope package was sterilized after disinfected and dried, differences between two packing methods as well as the preference of persons who operated endoscope was compared respectively. Results A total of 720 flexible endoscopes (including gastroscope, enteroscope and duodenoscope) were packed by two persons after cleaned, disinfected, rinsed and dried, methods A and B each packed 360 endoscopes. After sterilization, the indicator strip in two groups all changed color (100%). The average packing time of each endoscope in group A was (82.8±11.4) seconds, and that in group B was (23.6±3.4) seconds, with a significant difference (t=94.28, P<0.001); five bags in group A and two bags in group B were broken, there was no significant difference between two groups (χ²=0.577, P=0.447). Conclusion For the sterilization of flexible endoscope, paper-plastic bag with size of 25 cm×185 cm is convenient, time-saving and labor-saving, which meets the sterilization requirements of central sterile supply department, and is worth to be promoted in practical process.