For structure optimization of a groove type condenser,a three-dimensional finite element model of the groove type condenser was established based on MIDAS/Gen according to the groove type condenser devices located in Zhangjiagang testing ground. The method of Lanczos modes calculation was used in the model,the modal analysis was conducted under the conditions of different angles,and the structural mode characteristics of the groove type condenser were received under different working conditions. The dynamic characteristics were tested on the devices by arranging the measured points on different parts of the structure and placing sensors at the center of condensers. The dynamic signal acquisition system was used during the field measurement,the testing equipments and devices such as sensors and data acquisition instruments were used to capture the valid data of each measured point. The dynamic characteristics of groove type condenser were then acquired by processing the original data through the acquisition system. For verification of the analysis method,the finite element model was compared with the field measurements. The comparison results show that the three-dimensional finite element model can simulate the existing groove type condenser well,and it can be used in its static analysis and structure optimization analysis. In addition,the finite element modal can provide a scientific reference for further improvement on the concentrated effect of groove type condenser group and cost reduction.