The　Euler-Lagrangian　spray　and　atomization(ELSA)method　is　currently　the　leading　edge　algorithm　for　atomization　and　fragmentation,　and　the　model　conversion　is　one　of　the　key　techniques.　In　the　current　ELSA　model,　model　transformation　is　based　on　dividing　the　mesh　into　fixed　areas.　This　method　needs　to　determine　the　position　of　near-field　dense　area　and　far-field　boundary　according　to　the　experimental　results.　As　an　improvement,　there　is　a　dynamic　transformation　criterion　based　on　the　droplet　distance　and　liquid-phase　volume　ratio.　Base　on　the　existing　ELSA　transformation　thought,　We　dynamically　captures　the　Euler　liquid　mass　produced　when　the　liquid　film　at　the　front　of　the　liquid　column　breaks,　and　takes　the　sphericity　and　particle　diameter　as　the　criteria　to　convert　the　qualified　liquid　mass　into　Lagrangian　particles,　and　obtains　the　complete　process　of　liquid　column,　primary　breaking　and　secondary　breaking.　The　results　show　that　the　initial　droplet　comes　from　the　liquid　membrane　crushing　process.　The　ELSA　method　based　on　the　criterion　of　sphericity　and　particle　diameter　can　simulate　the　process　of　liquid　column　crushing　to　droplet　more　accurately　under　the　premise　of　ensuring　the　accuracy　of　spray　simulation.　©　2021,　Editorial　Office　of　Chinese　I.C.E.　Engineering.　All　right　reserved.