Abstract: Based on the theory of spherical perturbation,a measurement platform is designed for the cold model measurement in the construction of the linear accelerator,which realizes the high-precision,batch automatic cold model measurement of the cavity.At the same time,in order to reduce the influence of the vibration of the perturbation body on the measurement results,the modal analysis of the prestressed wire was carried out,and the optimal moving speed of the wire ball during the cold model measurement was obtained.Using this measurement platform,the radio frequency quadrupole field (RFQ) cavity of the 300 Me V proton heavy ion accelerator in the design was measured.The results show that the measurement platform has small measurement errors and good data repeatability and can be used as an important tool in the development of the linear accelerator cavity.