A master-oscillator power amplifier (MOPA) system based on Nd glass laser with output intensity of 5 GW/cm² is described. The laser operates at 1 Hz with pulse energy up to more than 4 mJ. The spatial profile is near top hat and the diameter is 1 mm, the temporal pulse shape is Gaussain and pulse width is about hundred picosecond. Frequency doubling efficiency is 37.5% with 3-mm-long BBO crystal, the pulse of microjoule output energy and 527-nm wavelength is achieved and used as the pump pulse in the short pulse optical parametric amplification, decreasing the parametric fluorescence influence to contrast of optical parametric chirped pulse (OPCPA) system.