  In this paper, we prove a reduction result on wide subcategories of abelian
categories which is similar to Calabi-Yau reduction, silting reduction and
$\tau$-tilting reduction. More precisely, if an abelian category $\mathcal{A}$
admits a recollement relative to abelian categories $\mathcal{A}'$ and
$\mathcal{A}"$, diagrammatically expressed by $$\xymatrix@!C=2pc{ \mathcal{A'}
\ar@{>->}[rr]|{i_{*}} && \mathcal{A} \ar@<-4.0mm>@{->>}[ll]_{i^{*}}
\ar@{->>}[rr]|{j^{*}} \ar@{->>}@<4.0mm>[ll]^{i^{!}}&& \mathcal{A''}
\ar@{>->}@<-4.0mm>[ll]_{j_{!}} \ar<EMAIL_ADDRESS>},$$ then the
assignment $\cc\mapsto j^*(\cc)$ defines a bijection between wide subcategories
in $\mathcal{A}$ containing $i_{*}(\mathcal{A}')$ and wide subcategories in
$\mathcal{A}"$. Moreover, a wide subcategory $\mathcal{C}$ of $\mathcal{A}$
containing $i_{*}(\mathcal{A}')$ admits a new recollement relative to
$\mathcal{A}'$ and $j^{*}(\mathcal{C})$ which is induced from the original
recollement.
