The　numerical　simulation　model　of　single　roller　melt　spinning　for　rapid　quenching　process　of　NdFeB　alloy　was　built,　and　the　vacuum　chamber,　cooling　roller　and　sample　were　taken　into　account　as　a　system.　The　existing　mature　technology　was　in　order　to　verify　the　correctness　of　simulation.　The　rapid　quenching　ribbons　with　different　roll　speeds　were　used　as　the　simulation　objects.　The　results　of　the　numerical　simulation　and　experiments　show　that　the　validity　of　the　model　has　been　testified　and　the　reasons　of　the　formation　of　complete　quenching　ribbons　and　by-product　have　been　explained.　The　experimental　thickness　of　the　ribbons　is　proportional　to　the　theoretical　thickness.　In　the　same　spray　condition,　with　the　roll　speed　increasing,　the　thickness　decreases　linearly.　At　the　speed　range　of　25-30　m　center　dot　s(-1),　the　simulated　calculation　date　is　close　to　the　experimental　date,　which　can　be　considered　as　an　ideal　technological　parameter.