The　fragmentation　and　naturalness　of　soils　make　their　deformation　and　strength　characteristics　have　obvious　scale　effects.　Therefore,　in　order　to　study　the　strain　localization　process　of　the　soils,　the　distribution　and　proportional　relationship　of　graded　particles　cannot　be　ignored,　and　the　macroscopic　mechanical　properties　must　be　characterized　from　multiple　scales.　Based　on　the　theory　of　cell　model,　the　soils　are　regarded　as　a　granular　material　composed　of　reinforced　particles　and　matrix.　The　intrinsic　scale　law　of　the　samples　with　different　reinforced　particle　sizes　is　studied　through　the　triaxial　compression　tests,　and　the　formation　process　and　initiation　mechanism　of　shear　band　at　meso　level　are　studied　through　the　numerical　simulation.　The　average　strain　energy　release　coefficient　is　introduced　to　quantitatively　verify　the　strain　energy　conversion　of　the　soils　after　reaching　the　peak　stress,　and　the　multi-band　initiation　and　progressive　competition　process　are　reproduced.　The　results　show　that　the　strength　tests　of　reinforced　particles　with　different　size　scales　indicate　that　the　discontinuity　of　particles　makes　the　soils　have　size　effects,　and　the　ratio　of　intrinsic　scale　to　particle　size　decreases　with　the　increase　of　the　reinforced　particle　size.　Before　the　stress　peak,　the　non-elastic　dissipative　energy　increases,　leading　to　strain　localization.　After　the　peak,　the　strain　rapidly　increases　within　the　shear　band,　while　there　is　a　rebound　outside　the　band.　©　2024　Chinese　Society　of　Civil　Engineering.　All　rights　reserved.