  We construct a quasiclassical framework for topological superconductors with
the strong spin-orbit coupling such as CuxBi2Se3. In the manner of the
quasiclassical treatment, decomposing the slowly varying component from the
total quasi-particle wave function, the original massive Dirac Bogoliubov-de
Gennes (BdG) Hamiltonian derived from the tight-binding model represented by 8
x 8 matrix is reduced to 4 x 4 one. The resultant equations are equivalent to
Andreev-type equations of singlet or triplet superconductors, in which the
apparent spin-orbit coupling vanishes. Using this formalism, we find a fact
that the odd-parity superconductivity in topological superconductors turns to
the spin-triplet one. % without the spin-orbit coupling through the
quasiclassical treatment. Moreover, in terms of the quasiclassical treatment,
we show that the topologically-protected zero-energy states in topological
superconductors has the correspondence to the Andreev bound states established
in a long history of studies for the unconventional superconductors. This
clearly indicates that low-energy non-trivial superconducting properties in the
topological superconductors can be analyzed by the established theoretical
descriptions on the spin-triplet superconductors.
