The ply angle misalignment has a significant influence on the surface accuracy of the carbon fiber reinforced polymer (CFRP) composite mirrors after curing. In order to investigate the sensitivity of two arrangement methods of layup sequences to the form error after cure, the finite element method (FEM) was used to discuss the influence. 18 different layup sequences have been investigated: 500 models with a normal distribution of random angular alignment errors were generated for each layup sequence, and the mirror’s deformation was calculated to obtain the values of mean M and standard deviation a of the surface error after curing. The results reveal that as the number of plies increases, the curing deformation of the two arrangement methods will gradually decrease; with the same number of plies at different increment angle, the “Optimized” sequences reduce M by about 8% to 16% relative to the clockwise sequences, which reduces a by about 9% to 22%. The improvement is obvious, especially when the number of plies is no larger than 24. This shows that the regularized stiffness coefficient method (corresponding to the “Optimized” sequences) can effectively reduce the form error compared to clockwise sequences; the general trend is that the smaller the optimization target value, the smaller the deformation; this positive correlation is established with a high probability under the same number of layers and the same increment angle, or when there is a large difference between the target values. The regularized stiffness coefficient method can get the layup sequence accurately, and thus has certain theoretical basis and manufacturing advantages. It is, therefore, a layup sequences design method worthy of study.