Q-switch erbium glass lasers have important application in eye-safe laser range finder. laser diode (LD) side-pumped erbium glass laser electro-optic Q-switch experiment is reported in this paper. An Q-switched laser pulse with energy of 5.5 mJ, pulse width of 94 ns, and repetition rate of 0.5 Hz is obtained. Experiment indicate that Q-switch delay time, pump rate and ion concentration are the major factors influencing the pulse width.