Yb:YAG ceramic slab with Cr 4+ :YAG edge cladding was fabricated by vacuum sintering technology using commercial powders as raw materials and CaO as a charge compensator. After annealing, a portion of Cr 3+ ions transform into Cr 4+ . The lasing wavelength of 1030nm of Yb 3+ lies within the Cr 4+ board absorption band range of 900–1100nm. The intensity of the Cr 4+ absorption peak is proportional to the Cr concentration. In order to keep the Cr:Ca molar ratio of 1:3, the amount of CaO grows accordingly with the increasing of the Cr concentration. If adding excessive CaO, abnormal grain growth and residual pores are easily generated. When the Cr concentration is 0.35at%, the comprehensive properties of the composite ceramic are the best among three samples. The interface region between Cr:YAG and Yb:YAG regions shows a uniform microstructure, indicating that there is no interface effect presence in the composite ceramic. The transmission of the sample is comparable to that of single crystal.