The　on-demand　modulation　of　defects　in　materials　for　the　effective　modulation　of　optical　nonlinearity　is　desirable,while　it　remains　a　great　challenge.In　this　work,we　demonstrate　that　electrochemical　activation　is　a　facile　and　convenient　approach　to　modulating　the　broadband　third-order　nonlinear　absorption　of　nanoporous　tungsten　oxide(WO3-x)thin　film.The　film　does　not　exhibit　optical　nonlinearity　at　the　initial　state,while　shows　a　distinct　saturable　absorption　under　an　applied　voltage　of-2.5　V　with　the　excitation　of　515,800,and　1,030　nm　laser.The　nonlinear　absorption　coefficient(βeff)is-766.38±6.67　cm·GW-1　for　1,030　nm　laser,-624.24±17.15　cm·GW-1　for　800　nm　laser,and-120.70±11.49　cm·GW-1　for　515　nm　laser,and　the　performance　is　competitive　among　inorganic　saturable　absorbers.The　activation　is　accomplished　in　2　min.The　performance　enhancement　is　ascribed　to　the　formation　of　abundant　in-gap　defect　states　because　of　the　reduction　of　the　tungsten　atoms,and　a　Pauli-blocking　effect　occurs　during　the　excitation　of　in-gap　defect　states.The　small　feature　size　of　WO3-x(-12　nm)enables　the　effective　and　fast　introduction　and　removal　of　the　defects　in　porous　film,and　accordingly　the　fast　and　broadband　modulation　of　optical　nonlinearity.Our　results　suggest　a　controllable,effective,and　convenient　approach　to　tuning　the　nonlinear　absorption　of　materials.