In　recent　decades,　loess　landslide　events　have　attracted　increasing　attention　in　the　South　Jingyang　tableland.　To　elucidate　the　mechanical　mechanism　of　landslide　initiation　in　the　region,　this　work　collected　undisturbed　loess　and　paleosol　samples　taking　from　the　Q2　strata　in　the　South　Jingyang　tableland.　A　range　of　direct　shear　tests　were　carried　out　to　explore　the　strength　evolution　law　of　shear　zone　soil　subjected　to　a　varying　initial　moisture　content.　In　addition,　soil　water　characteristic　curves　(SWCCs)　were　also　charted　and　used　for　predicting　the　unsaturated　shear　strength.　The　findings　show　that　the　basic　physical　properties　of　the　paleosol　are　different　from　those　of　loess　due　to　their　different　pedogenic　environments.　The　normal　stress　level　and　initial　moisture　content　jointly　determine　whether　the　shear　behavior　is　strain　hardening　or　strain　softening.　The　shear　strength　and　strength　parameters　evidently　diminish　with　an　increasing　initial　moisture　content,　and　cohesion　contributes　to　the　vast　majority　of　strength　attenuation.　Paleosol　samples　possess　higher　values　in　shear　strength　and　strength　parameters　than　loess　samples　due　to　their　stronger　inter-particle　cementation.　The　predictive　formulas　of　unsaturated　shear　strength　for　undisturbed　loess　and　paleosol　are　proposed,　respectively,　based　on　the　Vanapalli　model,　and　the　calculated　values　of　the　strength　prediction　model　are　in　perfect　agreement　with　the　experimental　values.　©　2024　by　the　authors.