A Q-switched Nd:YLF laser pumped by home-made MQW-LDA was developed. Pulse width, peak power were studied as functions of pumping energy, modulated depth, optical delay and reflectivity of the output coupling mirror in detail. Stable Q-pulse output (fluctuation <1%) was obtained with pulse energy of 0.8 μJ, FWHM of 70 ns, repetition of 100 Hz and optical to optical efficiency of 2.5%. When Q-switch and gain switch were applied the peak pulse power was increased and pulse width decreased. A comparison of experimental data with rate-equation theory was made, and agreed well.