Four single crystals (Yb_0.15Lu_0.85xY_0.85-0.85x)₃Al₅O₁₂ (x = 0, 0.25, 0.5, 1) were grown by the Czochralski method. The correlation of the host atom Lu:Y ratios with the density and the luminescence properties were revealed. The density increases linearly with increasing of Lu3+ content, which will improve the gamma ray cut-off ability. The integrated intensity of the X-ray excited luminescence spectrum increases exponentially with the increasing Y:Lu ratio, while the decay time becomes even shorter with the increasing Lu3+ content. These results will provide a basis to balance the comprehensive properties to match different application requirements.