We report an intense full-color emission originating from 5D0,1,2,3 to 7F0,1,2,3,4 transitions of Eu3+ in CaSc2O4 upon 395 nm excitation. The emission spectra vary with increasing Eu3+ concentration, demonstrating tunable color coordinates from white to red region in the CIE chromaticity diagram. Considering the relaxation from 5DJ to 5DJ−1 through cross energy transfer, the Eu3+ concentration dependent emission spectra are well simulated based on the analysis of steady state rate equations and the measured lifetimes of the 5DJ levels. It is suggested that CaSc2O4:Eu3+ could be a potential single-phased full-color emitting phosphor for near-ultraviolet InGaN chip pumped white light emitting diodes.