Ferroelectric tunnel junction (FTJ) exploiting the switchable polarization of ferroelectric material holds great potential for the low-power non-volatile memory. Recently, two-dimensional (2D) ferroelectric material CuInP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> (CIPS) which can provide ferroelectricity at the ultimate atomic-scale has been successfully introduced in FTJ to achieve significantly improved TER. Here, we present a theoretical study on the performance of FTJ based on CIPS through the quantum transport simulation using <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">kp</i> Hamiltonian obtained from density functional theory. Benchmarking with ferroelectric HfZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based FTJ reveals that much higher TER can be achieved in CIPS-based FTJ due to a lower tunneling potential barrier and a larger tunneling effective mass.