In order to realize the spot homogenization and beam shaping of high-power laser diode stack, a homogenization system is proposed based on double cylindrical lenses in the slow axis direction. The double cylindrical lenses are used to collimate beams of high fill factor laser diodes in the slow axis direction, for decreasing the numerical aperture of microlenses in the imaging multi-aperture integrator and reducing the homogenization system volume. Through three limiting conditions, the parameter ranges of the double cylindrical lenses are determined. By analyzing the effect of aberration on slow axis collimation, the double cylindrical lenses are optimized to achieve the remaining divergence angle of 1.74°. With the imaging multi-aperture beam integrator, the homogenization system for laser diode stack beams is designed and verified through experimental test. The experimental results show that the size of central spot on the target plane is about 6 mm×6 mm and the spot inhomogeneity reaches to 8.11%.