Abstract: 1.5 m LD pumped erbium ytterbium co-doped phosphate glass passively Q-switched microlaser was currently laser ranging military hotspots, and to achieve high laser pulse energy was particularly important. Experimental study of miniaturized laser was using of 940 nm diode laser as the pump source, Er3+/Yb3+ co-doped phosphate glass as the gain medium, Co2+: MgAl2O4 as a Q-switched laser crystal miniaturization. In order to obtain LD-pumped erbium ytterbium co-doped phosphate glass microlaser passively Q the best energy output condition, factors of the LD-pumped erbium ytterbium co-doped phosphate glass passively Q-switched laser output pulse energy were analyzed. A lot of experiments were done on pump laser output power conditions, the length of the gain medium, the output mirror transmission and other parameter. Eventually stable laser output was obtained with wavelength of 1.535 m, single pulse energy of 13 J, pulse of 6 ns, repetition rate of 10 Hz, beam quality of 1.2.