Based　on　the　Mohr-Coulomb　elastic-plastic　model　and　the　practical　engineering　background　of　Mopanshan　tunnel,　this　paper　applies　the　finite-difference　software　FLAC3D　to　simulate　and　analyse　the　whole　process　of　loess　tunnel　construction.　Then,　it　analyses　the　stability　of　the　surrounding　rock　and　sup-port　structure　after　partial　excavation　of　the　loess　tunnel　under　the　shallow　burying　and　unsymmetrical　load-ing　condition.　The　study　showed　that　in　the　absence　of　support,　the　shear　failure　occurred　to　the　top/upper　pilot　tunnel　of　the　tunnel　face,　the　failure　zone　under　tensile　stress　happened　to　the　shallow　soil　of　the　earth　surface,　and　the　soil　of　tunnel　face　appeared　to　be　damaged.　Finally,　according　to　the　analysis　results,　a　rea-sonable　construction　method　suitable　for　the　shallow　and　bias　loess　tunnel　is　determined.　©　2019　The　Authors,　published　by　EDP　Sciences.