The　flourish　of　two-dimensional　(2D)　materials　provides　a　versatile　platform　for　building　high-performance　electronic　devices　in　the　atomic　thickness　regime.　However,　the　presence　of　the　high　Schottky　barrier　at　the　interface　between　the　metal　electrode　and　the　2D　semiconductors,　which　dominates　the　injection　and　transport　efficiency　of　carriers,　always　limits　their　practical　applications.　Herein,　we　show　that　the　Schottky　barrier　can　be　controllably　lifted　in　the　heterostructure　consisting　of　Janus　MoSSe　and　2D　vdW　metals　by　different　means.　Based　on　density　functional　theory　calculations　and　machine　learning　modelings,　we　studied　the　electrical　contact　between　semiconducting　monolayer　MoSSe　and　various　metallic　2D　materials,　where　a　crossover　from　Schottky　to　Ohmic/quasi-Ohmic　contact　is　realized.　We　demonstrated　that　the　band　alignment　at　the　interface　of　the　investigated　metal-semiconductor　junctions　(MSJs)　deviates　from　the　ideal　Schottky-Mott　limit　because　of　the　Fermi-level　pinning　effects　induced　by　the　interface　dipoles.　Besides,　the　effect　of　the　thickness　and　applied　biaxial　strain　of　MoSSe　on　the　electronic　structure　of　the　junctions　are　explored　and　found　to　be　powerful　tuning　knobs　for　electrical　contact　engineering.　It　is　highlighted　that　using　the　sure-independence-screening-and-sparsifying-operator　machine　learning　method,　a　general　descriptor　WM3/exp(Dint)　was　developed,　which　enables　the　prediction　of　the　Schottky　barrier　height　for　different　MoSSe-based　MSJ.　These　results　provide　valuable　theoretical　guidance　for　realizing　ideal　Ohmic　contacts　in　electronic　devices　based　on　the　Janus　MoSSe　semiconductors.　©　2024　The　Royal　Society　of　Chemistry.