  A recent experimental study announced the emergence of superconductivity in
La$_3$Ni$_2$O$_7$ under pressure, with the highest observed superconducting
transition temperature ($T_c$) reaching approximately 80 K beyond 14 GPa. While
extensive studies have been devoted to the electronic correlations and
potential superconducting pairing mechanisms, there lack investigations into
the phonon properties and electron phonon coupling. Using density functional
theory in conjunction with Wannier interpolation techniques, we study the
phonon properties and electron phonon interactions in La$_3$Ni$_2$O$_7$ under
29.5 GPa. Our findings reveal that the electron phonon coupling is insufficient
to solely explain the observed high superconducting $T_c$ $\sim$ 80 K in
La$_3$Ni$_2$O$_7$. And the calculated strong Fermi surface nesting may explain
the experimental observed charge density wave transition in La$_3$Ni$_2$O$_7$.
Our calculations substantiate La$_3$Ni$_2$O$_7$ is an unconventional
superconductor.
