A　software　for　getting　various　order　elasto-optic　coefficient　tensors　which　belong　to　the　group　SO(2)　was　programmed　by　means　of　Matlab,　based　on　group　theory.　The　symmetrized　identity　representation　basis　functions　having　the　intrinsic　symmetry　of　elasto-optic　coefficient　tensors　were　developed　from　nonsymmetrized　identity　representation　basis　functions,　which　convenienced　programming.　The　form　of　second　order　nonlinear　strain　and　stress　elasto-optic　coefficient　tensors　having　the　symmetry　of　the　group　SO(2)　was　got　with　the　help　of　the　software,　and　its　invariance　under　arbitrary　rotation　about　the　Z-axis　in　physical　coordinate　system　was　verified　through　transformation　of　coordinates.