  We study mixed anomaly between $G_1$ and $G_2$ of one-form finite symmetry
$G_1\times G_2$ in $3d$ Chern-Simons theories. We assign a quantum entanglement
structure to two linked $G$-symmetry lines (Wilson loops) and compute the
entanglement entropy $S[G]$. We find a measure of the mixed anomaly by
computing $S[G_1\times G_2]-S[G_1]-S[G_2]$.
