Passively Q-switched solid-state lasers with short pulse width, high peak power are widely used in medical applications, optical communications, laser ignition and nonlinear optical conversion for generating new laser sources. Composite laser materials for passively Q-switched laser operation are successfully fabricated with thermal bonding technology and ceramic sintering technology. They alleviate the scattering and reflection loss induced in the surface of separated laser gain medium and saturable absorber, further mitigate the intracavity loss. Besides, composite laser materials eliminate the air gap between gain medium and saturable absorber. So the laser material damage is avoided and stable laser operation is maintained. Based on the potential applications of composite materials for passively Q-switched miniature, high peak power solid-state lasers, the advances and outlooks of passively Q-switched solid-state lasers based on Nd:YAG-Cr4+:YAG and Yb:YAG-Cr4+:YAG composite laser materials are reviewed in this paper.