Carbon fiber reinforced plastic (CFRP) laminates are sometimes adopted as material of space observation systems because their specific stiffness is high and thermal deformation can be controlled by stacking sequence and fiber orientation. However, unexpected out-of-plane thermal deformation is generated on CFRP laminate plates because of fiber orientation error. In this research, a CFRP reflector model was built and its thermal deformation was measured to determine the kinds of deformation generated on the reflector. In the experiment, non-axisymmetric deformation was generated even for uniform heating. Finite-element analysis (FEA) on thermal deformation of the reflector model was performed to explain non-axisymmetric deformation. FEA showed that non-axisymmetric deformation was generated by fiber orientation error. The thermal deformation of the CFRP reflector model was strongly affected by fiber orientation error, and accordingly, the fiber orientation angle of CFRP reflectors should be controlled strictly depending on the desired accuracy.