The Jiangmen Underground Neutrino Observatory is a multipurpose neutrino experiment designed to determine neutrino mass hierarchy and precisely measure oscillation parameters by detecting reactor neutrinos from the Yangjiang and Taishan Nuclear Power Plants, observe supernova neutrinos, study the atmospheric, solar neutrinos and geo-neutrinos, and perform exotic searches, with a 20-thousand-ton liquid scintillator detector of unprecedented 3% energy resolution (at 1 MeV) at 700-meter deep underground. In this proceeding, the subsystems of the experiment, including the cental detector, the online scintillator internal radioactivity investigation system, the PMT, the veto detector, the calibration system and the taishan antineutrino observatory, will be described. The construction is expected to be completed in 2021.