A　seismic　checking　method　of　engineering　structures　based　on　the　stochastic　semi-physical　model　of　seismic　ground　motions　is　developed.　Four　groups　of　stochastic　ground　motions　are　generated　using　the　stochastic　semi-physical　model　of　seismic　ground　motions.　In　conjunction　with　the　probability　density　evolution　method　(PDEM)　and　the　idea　of　the　equivalent　extreme-value　event,　the　dynamic　reliabilities　of　an　engineering　structure　are　evaluated.　The　dynamic　reliability　of　the　structure　is　taken　as　an　index　for　seismic　checking.　A　five-story　reinforced　concrete　frame　structure　is　analyzed　using　both　the　response　spectrum　method　and　the　proposed　method.　Some　features　of　the　instantaneous　probability　density　function　(PDF)　and　its　evolution,　the　extreme　value　distribution,　and　the　dynamic　reliability　are　discussed　and　compared　with　the　results　of　the　response　spectrum　method　in　the　Chinese　seismic　code.　The　seismic　checking　results　of　the　response　spectrum　method　show　that　the　structure　is　safe,　while　the　results　of　the　proposed　method　reveal　a　failure　probability　as　high　as　35.39%.　Moreover,　the　structure　has　such　different　reliabilities　when　it　is　excited　by　different　groups　of　simulated　seismic　ground　motions.　It　reveals　that　a　structure　designed　according　to　the　seismic　code　may　carry　a　high　risk　of　failure.　The　proposed　method　provides　a　more　accurate　way　for　the　evaluation　of　the　reliabilities　of　engineering　structures.