The　use　of　two-dimensional　materials　and　van　der　Waals　heterostructures　holds　great　potential　for　improving　the　performance　of　memristors　Here,　we　present　SnS2/MoTe2　heterostructure　synaptic　transistors.　Benefiting　from　the　ultra-low　dark　current　of　the　heterojunction,　the　power　consumption　of　the　synapse　is　only　19　pJ　per　switching　under　0.1　V　bias,　comparable　to　that　of　biological　synapses.　The　synaptic　device　based　on　the　SnS2/MoTe2　demonstrates　various　synaptic　functionalities,　including　short-term　plasticity,　long-term　plasticity,　and　paired-pulse　facilitation.　In　particular,　the　synaptic　weight　of　the　excitatory　postsynaptic　current　can　reach　109.8%.　In　addition,　the　controllability　of　the　long-term　potentiation　and　long-term　depression　are　discussed.　The　dynamic　range　(G(max)/G(min))　and　the　symmetricity　values　of　the　synaptic　devices　are　approximately　16.22　and　6.37,　and　the　non-linearity　is　1.79.　Our　study　provides　the　possibility　for　the　application　of　2D　material　synaptic　devices　in　the　field　of　low-power　information　storage.