The soft X-ray spectromicroscopy beamline is one of the first seven beamlines built in the first phase project of the Shanghai Synchrotron Radiation Facility (SSRF). It adopts an elliptically polarized undulator light source with high photon flux and good spatial coherence. Its photon energy is selected between 200eV and 2000eV, and this energy range covers the absorption edges of most of the important elements in the fields of biology, environment (soil, minerals), polymers, nanomaterials, etc., such as the K absorption edges of C, N, O, F, Na, and Mg, the L edges of Cl, K, Ca, Fe, Cu, and Zn in living cells. The scanning transmission X-ray microscopy (STXM) of this beamline combines the high spatial resolution (better than 30 nm, and up to 10 nm in combination with the CDI method) with the high chemical state resolution capability of near-edge absorption fine structure spectroscopy (NEXAFS), which enables the study of the properties of a wide range of physical states, such as solids, liquids, and soft matter, at the nanoscale.