Artificial　intelligence　devices　that　can　mimic　human　brains　are　the　foundation　for　building　future　artificial　neural　networks.　A　key　step　in　mimicking　biological　neural　systems　is　the　modulation　of　synaptic　weight,　which　is　mainly　achieved　by　various　engineering　approaches　using　material　design,　or　modification　of　the　device　structure.　Here,　we　realize　the　modulation　of　the　synaptic　weight　of　a　Ta2O5/ITO-based　all-metal　oxide　synaptic　transistor　via　laser　irradiation.　Prior　to　the　deposition　of　the　active　layer　and　electrodes,　a　femtosecond　laser　was　used　to　irradiate　the　surface　of　the　insulator　layer.　Typical　synaptic　characteristics　such　as　excitatory　postsynaptic　current,　paired　pulse　facilitation　and　long-term　potentiation　were　successfully　simulated　under　different　laser　intensities　and　scanning　rates.　In　particular,　we　demonstrate　for　the　first　time　that　laser　irradiation　could　control　the　quantity　of　oxygen　vacancies　in　the　Ta2O5　thin　film,　leading　to　precise　modulation　of　the　synaptic　weight.　Our　research　provides　an　instantaneous　(＜1　s),　convenient　and　low-temperature　approach　to　improving　synaptic　behaviors,　which　could　be　promising　for　neuromorphic　computing　hardware　design.