A　scheme　is　proposed　to　generate　W　state　of　N　atoms　trapped　in　a　cavity,　based　on　adiabatic　passage　along　dark　state.　Taking　advantage　of　adiabatic　passage,　the　atoms　have　no　probability　of　being　excited　and　thus　the　atomic　spontaneous　emission　is　suppressed.　The　scheme　is　simple.　It　does　not　need　to　adjust　the　interaction　time　accurately,　and　does　not　need　to　prepare　the　cavity　field　in　one-photon　state.　Numerical　simulation　shows　that　the　successful　probability　of　the　scheme　increases　with　the　increasing　of　the　atom　number.