Parametric　sensitivity　to　static　behavior　and　dynamic　characteristics　of　Long-span　Arch-truss　String　Structures　(ATSS),　which　is　based　on　statistical　distribution　of　parameter　errors　including　elastic　modulus　of　the　material,　effective　area　and　pre-stress　of　cable,　and　thickness　of　steel　pipe,　etc.,　was　studied　by　Monte　Carlo　simulation　method　of　ANSYS.　The　error　of　sectional　area　of　cable　is　found　to　be　the　most　sensitive　parameter　and　the　natural　frequencies　are　greatly　sensitive　to　the　errors　of　modulus　of　members.　The　results　help　to　determine　suitable　updating　parameters　of　ATSS,　and　provide　valuable　advices　to　guide　the　construction　control.