In order to meet the requirements for in-orbit thermal deformation measurements of satellite antenna panels， an accurate finite element model is required to simulate the thermal deformation process of the antenna panels. As the main structure of the antenna panel， the honeycomb sandwich panel usually needs to be simplified in the finite element modelling process， resulting in discrepancies between the finite element calculation results and the experimental measurement values. To address the above problem， thermal deformation experiments of the antenna plate structure under high temperature environment are carried out to obtain the temperature field distribution and thermal deformation displacement matrix. The finite element model thermal load is obtained by fitting the temperature field to it. On this basis， a method of finite element model updating based on the multi-island genetic algorithm is proposed to modify the model material parameters and boundary conditions using the root mean square error of the out-of-plane displacement measurement matrix of the antenna plate finite element model and the experimental model as the correction target. The prediction accuracy of the modified finite element model is significantly improved.