  We generalize the idea of symmetry topological field theory (SymTFT) for
subsystem symmetry. We propose the 2-foliated BF theory with level $N$ in
$(3+1)$d as subsystem SymTFT for subsystem $\mathbb Z_N$ symmetry in $(2+1)$d.
Focusing on $N=2$, we investigate various topological boundaries. The subsystem
Kramers-Wannier and Jordan-Wigner dualities can be viewed as boundary
transformations of the subsystem SymTFT and are included in a larger duality
web from the subsystem $SL(2,\mathbb Z_2)$ symmetry of the bulk foliated BF
theory. Finally, we construct the condensation defects and twist defects of
$S$-transformation in the subsystem $SL(2,\mathbb Z_2)$, from which the fusion
rule of subsystem non-invertible operators can be recovered.
