A novel design for a highly ecient 1-kHz single-frequency green laser is proposed. An ecient single-frequency laser pulse output at 532-nm wavelength may be obtained by combining the injection seeding with intracavity frequency doubling in a compact U-shaped cavity formed by two plano dichroic mirrors in an end-pumping arrangement. The laser is capable of producing green pulses with a total energy of 6.3 mJ at a pulse repetition rate of 1 kHz. The pulse width is about 10 ns and the optical–optical eciency from the 808-nm pump source to the 532-nm green output is around 12.7%.