This　paper　investigates　the　influence　of　the　hygroscopic　stress　field　on　the　natural　vibration　and　snap-through　dynamics　of　the　piezoelectric　bistable　asymmetric　laminated　composite　(BALC)　cantilever　plates.　A　theoretical　model　considering　the　hygroscopic　effects　is　established　and　validated　through　the　finite　element　(FE)　method　and　experiments.　The　impacts　of　the　moisture　absorption　and　geometric　parameters　on　the　vibration　responses　of　the　piezoelectric　BALC　cantilever　plates　are　analyzed.　The　third-order　shear　deformation　theory　and　von　Kármán　nonlinear　strain–displacement　relationships　are　utilized　for　the　modeling,　and　the　energy　equation　is　established.　The　multi-parameter　polynomial,　Chebyshev　polynomial　and　Rayleigh-Ritz　method　are　employed　to　determine　the　static　configurations　and　modes　of　the　piezoelectric　BALC　cantilever　plates.　The　force–displacement　relationship　is　derived　by　using　the　principle　of　the　virtual　work　for　the　static　snap-through　analysis.　The　results　indicate　that　the　moisture　ingress　affects　the　natural　characteristics,　bistable　characteristics,　reducing　curvature　and　altering　critical　load　thresholds.　Notably,　at　high　humidity　levels,　piezoelectric　BALC　cantilever　plates　exhibit　a　configuration　inversion　phenomenon.　This　paper　provides　a　theoretical　foundation　and　practical　guidance　for　designing　and　applying　the　piezoelectric　BALC　cantilever　plates　in　variable　moisture　environments.　©　2025　Elsevier　Ltd