Abstract: High-speed rotating equipment is used for isotope production in nuclear technology field, consisting of several machines as a mounting unit. The study on modal of block is the important method to guarantee the mechanical reliability of high-speed rotating equipment. In this paper, the model of high-speed rotating equipment block is built, and finite element method is adopted to analyze the modal frequency, into which the contact between the equipment and the support, the influence of the assembly preload, the gasket between bearing and support are taken account. Then compared with modal test result, the analysis result is used to identify the veracity of finite model. A new sensor layout method is proposed to optimize the modal test method of high-speed rotating equipment block in modal test which adopt the test method of single point excitation and multipoint pick-up. At last, the reasonable design parameters of support and assembly parameters are put forward by studying the influence of the support plate designing parameters and the thickness of gasket between bearing and support on the modal frequency.