Based on waveguide coupling technology, we set a kaleidoscope homogenizer to get an intensity redistributed uniform multimode laser beam and then shape the uniform beam into a large area square beam with an imaging system. The simulation results of overall light intensity uniformity are both greater than 89% under the irradiation areas of 3.5 cm × 3 cm and 10 cm × 10 cm. In the practical application, it is also greater than 85%. After that, we apply this technology to the photoluminescence imaging detection of semiconductor devices, proving that this technology can be widely used in a variety of research requiring large areas of uniform laser illuminating spots.