  By the standard theory, the stable $Q_{k+1,k}$-$Q_{k,k+1}/Q_{k}^{dc'}$
divergence-free element converges with the optimal order of approximation for
the Stokes equations, but only order $k$ for the velocity in $H^1$-norm and the
pressure in $L^2$-norm. This is due to one polynomial degree less in $y$
direction for the first component of velocity, a $Q_{k+1,k}$ polynomial. In
this manuscript, we will show a superconvergence of the divergence free element
that the order of convergence is truly $k+1$, for both velocity and pressure.
Numerical tests are provided confirming the sharpness of the theory.
