On the basis of element sensitivities of the observab1e matrix singu1ar - values , a technique to determine the locations of piezoe1ectric sensors of intelligent structures is presented in this paper. In order to obtain optima1 locations of sensors of intelligent structures , steps are taken as follows: firstly , a modal analysis of the initial structure is carried out with piezoelectric sensors on the given domain ; secondly , the observable modes corresponding to singular - values are taken with the singular - value decomposition method; thirdly , formulation of the e1ement sensitivity of the singular - value of controllability is developed; fourthly , the element sensitivity of the singu1ar - va1ues is chosen as the measure and the criterion to determine optima11ocations of sensors. A threshold va1ue is given and optimal produce is presented to determine which sensor e1ement needs to be kept/removed based on the sensitivity information. Locations of sensors are determined as the point where the element sensitivities of the singu1ar - va1ues are maximum. One numerica1 examp1e is taken to illustrate the app1ications of the present method.