In order to explore a 56-J high energy, high frequency lamp-pumped pulsed Nd:YAG solid-state laser, the main factors influencing the higher laser output energy are analyzed, the relation between output power and input power and reflectivity is simulated theoretically, and the effective measures to improve the efficiencies of the laser are brought forward. As a result, pulse width is tunable between 0.1 and 10 ms, frequency between 1 and 1000 Hz. When the input electrical power is 12 kW, the laser can output maximum single pulse energy of 56 J and average power of 500 W with the beam quality of 16.5 mm.mrad, total electro-optic efficiency of 4.2%, and the in stability of +-2% output power. It is indicated that the parameters corresponds with the results of theoretical analysis and simulation.