A laser diode (LD) pumped Er ³⁺,Yb³⁺:glass/Co²⁺:MgAl₂O_4composite material passively Q-switched miniature laser is reported for laser ranging.Er³⁺,Yb³⁺ co-doped phosphate glass is used as the gain medium,and Co²⁺:MgAl₂O _4is used as a Q-switched laser saturable crystal.The gain medium and a Q-switched rystal are compounded.The composite material can reduce the temperature gradient inside the gain medium,increase the thermal focal length a nd the mode volume,and improve the laser beam quality.In addition,the composite material reduces the ca vity loss,the density of the particles in the cavity increases,the pulse width becomes narrower,and the o utput energy increases, so that the laser performance is improved.Eventually,we get a wavelength is 1535nm awith repetition frequency of 10Hz.The center wavelength of pump source is 940nm.The single pul se energy is 210μJ,and pulse width is 2.8ns.The peak power is higher than 70kW,and beam quality of M^2is 1.2.