Drilling　path　optimization　is　one　of　the　key　problems　in　holes-machining.　This　paper　presents　a　new　approach　to　solve　the　drilling　path　optimization　problem　belonging　to　discrete　space,　based　on　the　particle　swarm　optimization　(PSO)　algorithm.　Since　the　standard　PSO　algorithm　is　not　guaranteed　to　be　global　convergent　or　local　convergent,　based　on　the　mathematical　model,　the　algorithm　is　improved　by　adopting　the　method　to　generate　the　stop　evolution　particle　once　again　to　obtain　the　ability　of　convergence　on　the　global　optimization　solution.　Also,　the　operators　are　proposed　by　establishing　the　Order　Exchange　Unit　(OEU)　and　the　Order　Exchange　List　(OEL)　to　satisfy　the　need　of　integer　coding　in　drilling　path　optimization.　The　experimentations　indicate　that　the　improved　algorithm　has　the　characteristics　of　easy　realization,　fast　convergence　speed,　and　better　global　convergence　capability.　Hence　the　new　PSO　can　play　a　role　in　solving　the　problem　of　drilling　path　optimization.