The present study focused on the structural, morphological, optical and fluorescence properties of Ni0.5-xMg0.5CuxFe2O4 (x = 0.0, 0.1, 0.3 and 0.5) nanoparticles synthesized by using auto combustion technique. The structural formation of the ferrite nanoparticles were confirmed by FTIR spectroscopic study. From FTIR spectra of the synthesized ferrite nanoparticles, metal ions are situated in two different sub lattices i.e. tetrahedral (A-site) and octahedral (B-site) in ferrites. The surface morphology and grain size of Cu substituted Ni-Mg ferrite nanoparticles were estimated from the micrographs of atomic force microscopy (AFM); the maximum grain size 54.69 nm was obtained. Spectra of UV-Visible absorption of the synthesized ferrite nanoparticles were carried-out by using UV-Vis spectrophotometry; the maximum absorption was observed at 418 nm. The energy band gap of ferrite nanoparticles has been estimated using UV-Vis absorption spectra; the energy band gap 3.50eV was obtained. From the fluorescence emission spectraof thesynthesized ferrite nanoparticles, ferrite samples emit red colour in the region of 680 nm.