Conventionally, a laser beam is amplified by making a single pass through an amplifier but the laser beam emitted from the oscillator generally has low energy, so the energy stored in the amplifier cannot be fully extracted and only low laser output power and overall efficiency result.According to the method of the invention for amplifying a solid-state laser, the laser beam is passed through the amplifier multiple times and with spatial uniformity so as to achieve efficient extraction of the energy stored in the amplifier and the thermally induced distortion of the laser beam can be compensated by the single amplifier.