Shanghai soft X-ray free-electron laser facility (SXFEL) is the first coherent X-ray light source in China with the shortest wavelength down to 2 nm. SXFEL is based on a 1.5 GeV C-band linac, including one seeded FEL line, one self-amplified spontaneous emission FEL line and five experimental stations. The development of SXFEL is in two stages, the test facility SXFEL-TF and the user facility SXFEL-UF. SXFEL-TF is based on a 0.84 GeV linac, aiming to master the key technologies of a cascaded FEL with high gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) scheme. Meanwhile, the object of SXFEL-UF is to start user operation at the end of 2019. This paper presents the design, construction and commissioning status of SXFEL.