Abstract: A mathematical model by Substruture Mode Synthesis Methed is provided for coupling vibration of a mistuned disk bladed.Several low order modes of each substructure are obtained by means of Experimental Modal Analysis and modifying calculation of the modes.Relying on the small perturbation of blade modal stiffiness,real mistuned disk bladed and several kinds of theoretical mistuned models are set up.Model parameters and mathematical formalas are checked by use of forced vibration experiment of a real mistuned disk bladed on vibrostand.Analytical results well reveal that the mistuning of blades is the reason why resonant response of some blade on the same stage disk is much greater than other blades.The results also show that smaller frequency difference and random mistuning distribution of blades are eligible,and also give the rational range of rotating frequencies of an engine.