  The bilayer nickelate La$_3$Ni$_2$O$_7$ (LNO) exhibits a remarkably
high-temperature superconductivity of approximately 80 K under pressure,
sparking considerable attentions. However, the nature of the spin, charge, and
orbital order in LNO remains unknown, hindering the exploration of the
mechanism of superconductivity. Here, supported by symmetry analysis and
density functional theory calculations, we unravel a double strip ground state
of LNO with alternating magnetic moments arrangements. Interestingly, a charge
density wave emerges under this determined magnetic order. Such CDW phase
exhibits a Pmnm space group with breathing deformation of the NiO$_6$
octahedra, where the stretching and shrinking of the octahedra correspond to
the formation of \emph{d}$_{z^2}^1$\emph{d}$_{x^2-y^2}^1$ and
\emph{d}$_{z^2}^1$ orbital order. Moreover, we build a first-principles-based
Hamiltonian for LNO, which provides deeper insight into its peculiar magnetic
order. Our work thus reveals a systematic spin-charge-orbital picture for LNO,
which can be extended to other nickelate-based superconductors, paving the way
for determining the mechanism of superconductivity.
