The present invention relates to a high-efficiency, multi-space-angel and dual-Z-shaped strip-structured laser amplifier device. According to the invention, based on the Z-type transmission between the upper and lower surfaces of a strip-shaped laser medium (1) along the Z-direction, the temperature gradient along the Z-direction is effectively compensated. Meanwhile, based on the Z-type round-trip transmission along the X-direction, the incident laser beam passes through the strip-shaped laser medium (1) for multiple times. In addition, by means of a laser beam extraction device, the laser beam shoots into the strip-shaped laser medium for multiple times at different space angles, so that the dual-Z-type operation is realized for multiple times. Fill factors are fully increased and the energy in a gain medium is effectively extracted. The amplification of the laser power is ensured to be high in efficiency and high in gain. The device is particularly suitable for the power amplification of the small-power seed laser or the low-gain-wavelength laser. In this way, the high-efficiency and high-gain laser amplification is realized.