With　the　continuous　development　of　national　economy　and　the　construction　technology,　a　lot　of　large-span　spatial　structures　with　unique　form　and　complex　construction　are　emerging.　The　health　monitoring　system　that　mainly　used　in　bridge　structure　is　applied　in　large-span　spatial　structures　gradually.　Parameter　identification　and　damage　alarming　are　the　core　technology　of　health　monitoring.　In　this　paper　some　structural　modal　parameter　identification　methods　based　on　ambient　excitation　are　introduced.　Finally,　for　large　span　structures　with　characteristics　of　low-intensive　modes,　the　response　data　based　on　large　span　structures　for　modal　parameter　identification　method　was　summed　up,　and　the　critical　issues　for　further　research　in　this　field　are　also　presented.