In　order　to　obtain　the　optimal　compactness,　the　design　method　of　particle　gradation　of　soils　needs　to　be　improved　and　optimized.　In　this　work,　based　on　the　fractal　theory　and　h　urnas　equation，a　gradation　governing　equation　(named　F-F　equation　)　suitable　for　describing　soils　of　continuous　gradation　is　derived,　and　furthermore　an　optimized　method　for　easily　determining　particles　size　distribution　is　proposed.　The　laboratory　consolidation　tests　are　carried　out　to　study　the　deformation　differences　among　the　specimens　prepared　by　optimized　grading　and　9　groups　of　well-graded　sand　specimens,　in　order　to　verify　the　advantage　of　proposed　grading　optimization　method.　A　numerical　model　which　can　reflect　the　deformation　characteristics　of　soil　specimens　is　established　using　particle　flow　software　PFC.　After　verifying　the　effectiveness　of　numerical　model　by　comparing　the　simulation　results　with　laboratory　test　results,　6　groups　of　uniaxial　compression　numerical　tests　of　graded　gravel　are　carried　out.　The　results　show　that　F-F　optimization　equation　of　particle　gradation　is　widely　applicable　to　different　particle　size,　such　as　sand　or　gravel.　Compared　with　the　coefficient　of　uniformity　Cu，coefficient　of　cun　ature　C(.　and　fractal　gradation　method,　the　proposed　gradation　optimization　method　does　not　contain　empirical　parameters,　and　has　distinct　superiority　and　wider　applicability　in　efficient　control　of　soil　compaction.　©　2023　Editorial　Office　of　China　Civil　Engineering　Journal.　All　rights　reserved.