To　meet　the　needs　of　wheelchair　users　who　wish　to　change　their　body　posture　to　facilitate　their　life　and　move　freely　in　complex　environments,　this　study　designs　a　wheelchair　with　functions　of　posture　adjustment　and　overcoming　obstacles.　After　analysis　of　these　specific　needs,　the　wheelchair　structure　is　designed　based　on　modular　design　principle　to　include　a　chair　and　mobile　module.　The　chair　module　comprises　back-posture　adjustment　and　sliding　mechanisms,　and　the　mobile　module　comprises　front,　main,　and　auxiliary　wheel-leg　mechanism.　In　particular,　the　main　and　auxiliary　wheel-leg　mechanisms　are　the　main　structures　for　wheelchair　movement.　The　different　schemes　are　then　compared　and　analyzed.　On　this　basis,　the　kinematic　models　of　each　mechanism　are　established　and　the　motion　performance,　including　posture　adjustment　and　ability　to　overcome　obstacles,　is　analyzed　in　detail.　Analysis　of　the　mechanical　properties　provides　a　basis　for　the　selection　of　driving　components.　The　control　system　is　designed,　and　the　prototype　of　multifunctional　wheelchair　is　developed.　Experimental　results　show　that　the　wheelchair　can　realize　the　adjustment　of　body　posture　and　complete　the　process　of　moving　up　and　down　steps　with　good　user　stability.　The　wheelchair　can　considerably　facilitate　the　movement　of　the　disabled　or　the　elderly.