For example in gaussian.
If I use mixed basis(basis mixed), the orbital symmetry will not be printed. What should I do?
This is not possible with mixed basis sets, and for good reason: with BASIS=MIXED, there is no guarantee that the user won’t specify different basis sets for symmetry-equivalent atoms. Doing so would break the point-group symmetry and thus invalidate the symmetry labels. With BASIS=GEN (where every instance of element X must have the same basis set, symmetry labels are printed, just like they are for “named” basis sets.