Abstract: Objective To investigate hygienic status of secondary water supply to the aircrafts in Dalian Airport and to provide references for qualified water supply management for aircrew and passengers.Methods Water samples of secondary water supply were collected and detected according to the Drinking Water Standard Examination Method(GB/T5750-2006);the detection results were then evaluated according to the Hygiene Standard for Drinking Water(GB5740-2006) during the period from 2013 to 2015;the hygienic indicators in the survey included microbial indexes, free residual chlorine, pH value, and sensory property indexes.Results For the 204 water samples detected during the period, the overall qualification rate of hygienic indicators was 67.16%, with the highest rate of 83.93% in 2013 and the lowest rate of 50.57% in 2015.The hygienic indicators with lower overall qualification rate included total bacterial count(72.06%), total coliforms(99.02%), free residual chlorine(86.27%), and pH value(80.88%).The overall qualification rates were 78.95%, 63.79%, and 51.85% for the samples of tap water from secondary pump station, transported water from water trucks, and tap water from aircrafts, with a significant difference(P<0.05).Conclusion The hygienic status of secondary water supply to aircrafts by an airline in Dalian Airport needs to be improved to control related potential health risk, particularly for free residual chlorine and bacterial contamination.