Elasto-plastic　response　time-history　analyses　of　a　long-span　hangar　based　on　site-class　IV　were　performed　under　3　seismic　inputs　of　rare　major　earthquake　for　the　seismic　fortification　intensity　of　7,　using　direct　integration　method.　Dynamic　responses　of　the　structure　subjected　to　one-dimensional　and　three-dimensional　earthquake　inputs　were　compared.　The　results　show　that,　with　three　multi-dimensional　earthquake　inputs,　more　plastic　hinges　of　its　supporting　columns　appeared,　and　for　some　of　them,　the　plastic　damage　got　worse;　The　maximum　lateral　displacements　of　the　structure　and　the　maximum　internal　forces　of　its　columns　are　increased　slightly;　whereas,　the　roof　structure　were　influenced　more　obviously,　the　number　of　hinges　and　internal　forces　of　roof　members　got　significantly　increased.