  We prove that for all $s\in(0,d)$ and $c\in (0,1)$ there exists a
self-similar set $E\subset \mathbb{R}^d$ with Hausdorff dimension $s$ such that
$\mathcal{H}^s(E)=c|E|^s$. This answers a question raised by Zhiying Wen[16].
