Single crystal of Ho~(3+),ytterbiumcodoped yttrium aluminum tetraborate Ho~(3+),Yb~(3+):YAl_3(BO_3)_4(Ho,Yb:YAB) has been grown by the flux method.The absorption spectra in the visible and NIR regions of Ho,Yb:YAB crystal were measured at room temperature;we calculated the intensity parameters,the spontaneous emission probabilities and stimulated emission cross sections of Ho~(3+) in Ho,Yb:YAB crystal by Judd-Ofelt(J-O) theory.The fluorescence spectra of Ho,Yb:YAB crystal were also measured at room temperature excited by 976 nm laser.The strong NIR emission peaks located at 1 921 nm was observed,and the visible up-conversion luminescence has been found.