Abstract: Response of laminated composite structures to,thermal surroundinks has been a subject of intensive studies in recent years.The thermal behaviors of laminated composite plates and shells have studied well.In this paper,the thermal deformations and stresses in stiffened composite laminates are investigated by using finite element method.Based on Mindlln hypothesis,laminated composite plate and beam theories including the effct of transverse shear deform ationane given.The fosegoingtheories arr also applicable to thick plates and bea ms.The thermal loadings considere dare transient as well as steady.The corresponding computer code are developed The application of the present model and code to practical problemshas shown that they are accurate and effective.