Inertial　microfluidic　technology　has　emerged　as　a　highly　promising　approach　for　the　separation　of　particles/cells,　characterized　by　high　throughput　and　label-free　features.　This　study　presents　a　novel　inertial　microfluidic　chip　design　that　enables　the　continuous　separation　of　target　particles　at　low　Reynolds　numbers　(Re　＜=　36).　To　enhance　its　sorting　performance,　the　influences　of　Reynolds　numbers　(Re　=　3.7-60),　particle　sizes　(d　=　10　and　20　mu　m),　and　outlet　flow　rates　on　the　particle　separation　efficiency　and　purity　are　further　examined,　and　a　phase　diagram　of　the　optimal　working　conditions　is　obtained.　The　evolution　of　the　flow　field　structure　within　the　microfluidic　chip　is　comprehensively　analyzed,　which　can　be　divided　into　three　distinct　regions,　namely,　the　main　flow,　sheath　flow,　and　vortex.　The　mechanism　of　particle　migration　behavior　across　curved　streamlines　is　further　explored.　This　device　can　achieve　a　maximum　separation　efficiency　of　94%　for　target　large　particles　(d　=　20　mu　m),　with　a　fivefold　increase　in　the　enrichment　concentration,　a　31.3-fold　increase　in　purity,　and　a　removal　efficiency　of　small　particles　reaching　97.1%.　The　results　demonstrate　that　this　device　can　facilitate　the　continuous　and　direct　separation　of　target　larger　particles　based　on　their　size,　presenting　numerous　advantages,　such　as　a　short　microchannel　length,　low　Reynolds　number,　minimal　cell　damage,　and　ease　of　operation.　Hence,　this　method　represents　an　easy-to-use　and　straightforward　approach　for　microfluidic　sorting　techniques　and　is　anticipated　to　have　practical　application　in　the　sorting　of　rare　circulating　tumor　cells　from　complex　cell　solutions.