Abstract: Modal iteration is a kind of classic technique in solving mode shapes,it is used in FEM software or other numerical area.The paper advanced experimental modal iterative method along with classic numerical modal itera-tion.Exciting force can be introduced by assumptive mode shape and steady response will be seized. It can get proto-type mode shapes.The idea of experimental modal iterative method is compeletely different from current resonance test to get mode shapes.It adjusts amplitude ad phase at same time and needs less test period.Mode shapes purity is re-lated with resonance frequency precision only. The complexity of exciting force adjusting is independent with shaker number. This technique can reduce resonance test work greatly.