  In this paper, we derive the second variation formula of pseudoharmonic maps
into any pseudo-Hermitian manifolds. When the target manifold is an isometric
embedded CR manifold in complex Euclidean space or a pseudo-Hermitian immersed
submanifold in Heisenberg group, we give some conditions on Weingarten maps to
obtain some unstability of pseudoharmonic maps between these pseudo-Hermitian
manifolds.
