  In this paper, we construct the quasi-normal modes of three-dimensional
extremal black holes in an algebraic way. We show that the infinite towers of
the quasi-normal modes of scalar, vector and tensor could be constructed as the
descendents of the highest weight modes. Our investigation shows that the
hidden conformal symmetry suggested in arXiv:1007.4269 is an intrinsic property
of the extremal black hole. Moreover, we notice that we need to fix the freedom
in defining the local vector fields and find the right hidden conformal
symmetry to obtain the physical quasi-normal modes.
