Double laser diode array (LDA) alternate symmetric side-pumped Nd:YAG laser is developed.The 1064 nm dynamic-laser output has been obtained by electro-optic (E-O) Q-switch.The perfect matching of gain field inside of the crystal and fundamental mode of cavity can be made by this structure,and high beam quality,high power output and high extraction efficiency can be easily obtained.The pumping source is the LD array which the peak power of one module is 100 W,and a direct close-pumping configuration and KD*P crystasal as E-O Q-switch are used for the laser in the experiment chooses.By using the ABCD propagation law of Gaussian beams,the stability-area of resonant cavity is calculated and the more reasonable parameters of resonant cavity are offered.When the repetition frequency is 20 Hz and the pumping energy is 1200 mJ,the 1064 nm dynamic-laser output with 151 mJ output energy and 8.48 ns pulse width is obtained,and the conversion efficiency of light-light is 12.6%.