The purpose is to study the CR-manifold with a contact structure conformal to the Heisenberg group. In our previous work [WY17], we have proved that if the Q ′ -curvature is nonnegative, and the integral of Q ′ -curvature is below the dimensional bound c ′ 1 , then we have the isoperimetric inequality. In this paper, we manage to drop the condition on the nonnegativity of the Q ′ -curvature. We prove that the volume form e 4u is a strong A ∞ weight. As a corollary, we prove the Sobolev-Poincaré inequality on a class of CR-manifolds with integrable Q ′ -curvature.