  Let $h=\prod_{i=1}^{t}p_i^{s_i}$ be its decomposition into a product of
powers of distinct primes, and $\mathbb{Z}_{h}$ be the residue class ring
modulo $h$. Let $1\leq r\leq m\leq n$ and $\mathbb{Z}_{h}^{m\times n}$ be the
set of all $m\times n$ matrices over $\mathbb{Z}_{h}$. The generalized bilinear
forms graph over $\mathbb{Z}_{h}$, denoted by
$\hbox{Bil}_r(\mathbb{Z}_{h}^{m\times n})$, has the vertex set
$\mathbb{Z}_{h}^{m\times n}$, and two distinct vertices $A$ and $B$ are
adjacent if the inner rank of $A-B$ is less than or equal to $r$. In this
paper, we determine the clique number and geometric structures of maximum
cliques of $\hbox{Bil}_r(\mathbb{Z}_{h}^{m\times n})$. As a result, the
Erd\H{o}s-Ko-Rado theorem for $\mathbb{Z}_h^{m\times n}$ is obtained.
