The seismic responses of engineering structure can be dramatically reduced by the energy dissipation from tuned mass damper (TMD). For the actual eccentric structure, the eccentricity values are hard to be determined, however, the control efficiency will decline if the TMD is simply installed not considering the real eccentricities. Hence, the optimal install location of TMD needs to be studied in details. Under the condition that the eccentricity of actual multidimensional structure is difficult to be obtained accurately, a parameter identification method based on extend Kalman filter (EKF) is presented in order to simultaneously identify the structural mass, the horizontal stiffness and the eccentricities in two horizontal vectors, thus the optimal location of TMD can be determined based on the real physical parameter. As an example, an asymmetric reinforced concrete frame structure is analyzed based on free vibration responses and EKF, and the parameters such as the integrated eccentricities are accurately identified, and the seismic responses for different locations of TMD are compared. The results show that the parameters can be identified accurately with EKF, and best control rate can be obtained after choosing the rational locations, this method has superior feasibility in engineering practice.