As　the　whole　society　attaches　great　importance　to　the　safety　of　food　and　medicine,　and　hydrogen　fuel　cell　and　new　energy　vehicle　industry　rises　suddenly,　people＇s　requirements　for　clean　compressed　air　is　more　and　more　urgent.　Water-lubricated　single　screw　compressor　is　an　ideal　choice　for　providing　clean　air　because　of　the　advantages　of　balanced　force,　a　long　service　life,　and　high　efficiency,　and　the　influencing　factors　of　its　performance　have　received　more　and　more　attention.　This　study　established　a　mathematical　model　of　the　working　process　of　a　water-lubricated　single-screw　air　compressor　to　study　the　relationship　between　its　performance　and　the　water　injection　atomization.　The　model　considered　leakage　and　heat　transfer　between　water　and　moist　air　and　analysed　the　influences　of　droplet　diameter　and　rotation　speed　on　compressor　performance.　The　results　showed　that　water　injection　atomization　can　effectively　reduce　the　discharge　temperature,　make　the　compression　process　of　the　compressor　tend　to　isothermal　compression.　Under　rated　conditions,　a　reduction　in　the　droplet　diameter　from　0.25　mm　to　0.15　mm　reduced　the　discharge　temperature　of　the　compressor,　improved　the　volume　efficiency,　and　improved　the　adiabatic　efficiency　by　31　K,　2.6%,　and　8.2%,　respectively.　©　2021　The　Authors,　published　by　EDP　Sciences.