  The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose
neutrino-oscillation experiment designed to determine the neutrino mass
hierarchy and to precisely measure oscillation parameters by detecting reactor
antineutrinos, observe supernova neutrinos, study the atmospheric, solar
neutrinos and geo-neutrinos, and perform exotic searches, with a 20 kiloton
liquid scintillator detector of unprecedented $3\%$ energy resolution (at 1
MeV) at 700-meter deep underground and to have other rich scientific
possibilities. Currently MC study shows a sensitivity of the mass hierarchy to
be $\overline{\Delta\chi^2}\sim 11$ and $\overline{\Delta\chi^2}\sim 16$ in a
relative and an absolute measurement, respectively. JUNO has been approved by
Chinese Academy of Sciences in 2013, and an international collaboration was
established in 2014. The civil construction is in preparation and the R$\&$D of
the detectors are ongoing. A new offline software framework was developed for
the detector simulation, the event reconstruction and the physics analysis.
JUNO is planning to start taking data around 2020.
