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Based on the demand for high-power output, a spatial beam combining 7-channel quantum cascade lasers (QCLs) is demonstrated in this paper. A “2 + 3 + 2” stepped structure is designed to convert the seven beam spots into a circular arrangement. An aspherical lens with a large numerical aperture (NA) of 0.85 and a focal length of 1.873 mm is used in each single QCL for collimation, and seven reflectors are utilized in the 7-channel QCLs combined in the spatial beam. After combining the spatial beam, the maximum continuous output power of the system is 3.6 W, and the beam quality M² is 5.59 in the fast axis and 8.3 in the slow axis, respectively.