Aiming at the phenomenon of thermal-induced vibrations and escape times in the operation of large flexible appendages on spacecraft, and constructs a dynamic model with constraints considering the influence of thermal effects on the large flexible thick plate structures. The study investigates the effects of plate thickness, plate length, and solar radiation incident angle on the escape time. This paper assumes that the solar radiant thermal load uniformly loaded at the surface of the plate and only transfers in the thickness direction, combine with theories of continuum mechanics, establish the expression for the elastic force of a flexible plate element which considering the thermal effect. Based on the ANCF and Mindlin plate theory, combine with the Lagrange multiplier method, build the dynamic model of the large flexible thick plate which constraint are obtained, and itsdynamic response is solved. On this basis, using numerical simulation, the influence of factors such as plate, plate length, and solar radiation incident angle on the escape phenomenon in thermal-induced vibrations is analyzed.