Monoclinic Yb3+-doped KLu(WO4)2 (Yb:KLuW) crystal with large sizes was grown by top-seeded solution growth (TSSG) method. Room-temperature absorption and fluorescence spectra were measured. The ground-state energy-level splitting was 562 cm-1. The absorption cross section, peak emission cross section as well as the minimum inversion fraction ?min and the minimum absorbed pump intensity Imin were calculated. The measured emission lifetime was 0.676 ms and the emission spectral bandwidth (FWHM) was up to 55 nm. In comparison with established laser crystals the results suggested that this crystal has potential application in efficient tunable and femtosecond laser operation. The room-temperature absorption and fluorescence spectra were measured. The ground-state energy-level splitting was (Monoclinic Yb3 + -doped KLu (WO4) 2 (Yb: KLuW) crystal with large sizes was grown by top- seeded solution growth 562 cm-1. The absorption cross section, peak emission cross section as well as the minimum inversion fraction? Min and the minimum absorbed pump intensity Imin were calculated. The measured emission lifetime was 0.676 ms and the emission spectral bandwidth (FWHM) was up to 55 nm. In comparisonCompare laser crystals the results suggests that this crystal has potential application in efficient tunable and femtosecond laser operation.