This paper describes the design of general arrangement, resonant cavity, optical condenser, frequency doubler and cooling system of the BPJ-1 frequency doubled Nd:YAG laser. Laser parameters are as follows: pulse energy 0.3 j, pulse duration<4.5 ns, beam divergence<1 mr, repetition frequency 1 pps, efficiency for frequency doubling >45%, the device can operate continuously for 30 minutes.