Gain-switching dynamics of laser diode array (LDA) end-pumped Nd:YAG lasers was studied in detail by means of mathematical calculation of the rate equtions. Pulsed laser output at 1.06 4μm wavelength with peak power of nearly 200 mW and pulse width less than 200 ns has been obtained by gain switching of a LDA (λP = 0.808μm) end-pumped Nd:YAG laser. The experimental results are in agrement with those of theoretical calculations.