[en] Manganese-doped ZnS nanoparticle was synthesized through a room-temperature wet-processing method. The ZnS:Mn2+ nanophosphor showed the particle size of about 4 nm, and a single phase of cubic structure compared with the bulk sample with double phases of cubic and hexagonal structures. Yellow Mn2+ emission peak showed the redshift by about 15 nm compared with the bulk sample due to the increased field strength resulting from the quantum confinement effect. Especially, with increasing temperature, the yellow emission of the nanophosphor showed the blueshift in the peak position due to the decreased field strength resulting from the lattice expansion. With increasing temperature, the yellow emission of the nanophosphor increases and then decreases. It can be described in terms of two competing factors of the thermal release of trapped charges and the phonon-electron interaction.