The phase behaviors of multiblock terpolymer A(BC)(n)B (or A(BC)(n)) with equal volume fractions of A and compositional symmetric (BC)(n)B (or (BC)(n)) are investigated by using the pseudospectral method of the self-consistent mean field theory. These terpolymers can self-assemble into hierarchical lamellar phases of perpendicular or parallel lamellae within lamellae, and the number of B/C thin layers in the parallel phase can be varied. The relative stability among these hierarchical lamellar phases can be tuned by the three interaction parameters of chi N-AB, chi N-AC, and chi N-BC. Two-dimensional phase diagrams, the cross sections of the three-dimensional phase diagram, are determined in our calculations. Our conclusion that the perpendicular phase is stable only in the case of chi N-AC << chi N-AB < chi N-BC is consistent with experimental observations by Bates's group. In addition, our results suggest that the existence of the perpendicular phase is generic in both types of terpolymers: A(BC)(n)B and A(BC)(n), with different values of n, even for the special case of A(BC)(n), that is, an ABC linear terpolymer.