The　effects　of　medium　viscosity　on　the　spray　flow　rate,　spray　Sauter　Mean　Diameter,　droplet　velocity　and　spray　cone　angle　of　pressure　swirl　nozzles　are　investigated　by　making　use　of　the　particle　dynamics　analysis　system　and　high-speed　photographic　system.　Based　on　the　axial　and　radial　distribution　characteristics　of　Sauter　Mean　Diameter　and　droplet　velocity,　the　water-glycerol　mixture　is　used　to　simulate　medium　with　a　wide　range　of　viscosities.　It　is　found　that　with　the　increase　of　viscosity,　the　turbulence　of　the　medium　flow　and　the　swirling　effect　is　weakened,　and　the　rated　pressure　becomes　larger　and　the　spray　flow　rate　increases.　Spray　Sauter　Mean　Diameter　and　droplet　axial　velocity　becomes　larger,　while　the　spray　cone　angle　decreases.　The　development　of　the　axial　velocity　distribution　of　spray　cone　is　characterized　by　the　radial　and　axial　position　parameters.　The　area　of　the　large-droplet　region　on　both　sides　of　spray　cone　becomes　larger,　and　the　area　of　small-droplet　region　near　the　axis　becomes　smaller.