A conductively cooled, laser diode (LD) end-pumped, injection-seeded single-frequency Nd:YAG laser is designed and implemented. The laser is capable of producing an 8-mJ Q-switched pulse with a 11-ns pulse width at 1 064 nm and at a pulse repetition rate of 1 000 Hz. At the maximum output energy of 8 mJ, the frequency jitter is less than 3.5 MHz (root mean square (RMS)) over two minutes, and the linewidth is around 54.2 MHz. The M2 of the laser beam is approximately 1.30 in both horizontal and vertical directions. The optimized ramp-fire technique is applied to build reliable single longitudinal mode oscillating.