Inter-story　stiffness　identification　of　shearing　structures　under　ambient　excitation　was　studied　and　a　new　method　was　presented.　In　the　method,　the　transition　from　structural　random　response　to　deterministic　response　was　realized　by　the　natural　excitation　technique　(NExT).　The　parameter-decoupled　free　vibration　equation　of　shearing　structures　was　deduced,　and　the　equation　could　simplify　the　process　of　identification　and　reduce　the　amount　of　calculation.　Through　the　effective　combination　of　the　NExT,　the　parameter-decoupled　method　and　the　extended　Kalman　filter　(EKF)　algorithm,　a　good　scheme　was　presented　for　inter-story　stiffness　identification　of　shearing　structures　under　ambient　excitation.　Using　a　shearing　structure　with　six-degree-of-freedom　as　example,　the　scheme　was　tested　by　numerical　simulation.　The　results　show　that　the　inter-story　stiffness　can　be　identified　basically　with　accuracy,　and　the　scheme　can　be　applied　in　practical　projects　for　health　monitoring　of　shearing　structures.