In this paper, we prove that the lower triangular matrix category
$\Lambda =\left [ \begin{smallmatrix} \mathcal{T}&0\\ M&\mathcal{U} \end{smallmatrix} \right ]$
, where
$\mathcal{T}$
and
$\mathcal{U}$
are
$\textrm{Hom}$
-finite, Krull–Schmidt
$K$
-quasi-hereditary categories and
$M$
is an
$\mathcal{U}\otimes _K \mathcal{T}^{op}$
-module that satisfies suitable conditions, is quasi-hereditary. This result generalizes the work of B. Zhu in his study on triangular matrix algebras over quasi-hereditary algebras. Moreover, we obtain a characterization of the category of the
$_\Lambda \Delta$
-filtered
$\Lambda$
-modules.