The invention relates to the field of laser technologies, in particular to a method and a device for generating a high-energy pulse packet. The device comprises a pulse source, a pulse multiplication widening device, a nonlinear amplification system and a pulse compression device which are connected in sequence, wherein the pulse source is used for providing a single pulse light source; the pulse multiplication widening device is used for transforming single pulse output by the pulse source into multi-pulse output having an overlap area on a time axis and providing necessary conditions for generation of the pulse packet, wherein the number N of multiple pulses is not less than 2 and the pulse interval can be adjustable; the nonlinear amplification system is used for amplifying multiple pulses output by the pulse multiplication widening device and outputting high-energy optical pulses; the pulse compression device is used for compressing the amplified high-energy optical pulses and outputting the high-energy pulse packet. The method and the device for generating the high-energy pulse packet, which are provided by the invention, have the advantages of simple structure and high conversion efficiency, the high-energy, narrow-pulse and high-peak pulse laser output can be realized, and the method and the device can be widely applied to the fields, such as precise machining, laser radar and weapon and laser medicine.