Flashing　spray　is　a　common　phenomenon　which　finds　many　applications　in　the　industry,　such　as　flash-spray　internal　combustion　engine,　distillation　of　salt　water　by　flashing　evaporation,　cryogen　spray　cooling　in　dermatology.　In　order　to　improve　the　understanding　of　atomization　mechanism,　this　paper　presents　an　experimental　investigation　to　the　droplets　dynamics　in　the　R134a　flashing　spray　including　the　variations　of　droplets　diameter　and　velocities.　The　droplets　diameter,　droplets　axial　velocity　and　radial　velocity　at　different　locations　are　simultaneously　measured　by　the　PDPA　system.　The　PDPA　measurements　data　find　that　both　the　non-dimensional　velocities　show　self-similar　profile.　Two　empirical　equations　have　been　proposed　to　describe　the　non-dimensional　velocities.