A beam shaping method for laser diodes stack by superposition of tilted fundamental mode Gaussian beams to form a nearly uniform illumination is proposed. The analytical formula for average intensity of the multi-tilted Gaussian beams (MTGB) propagating is derived and used to study the uniform properties of the beam profile by the Fourier analysis method. It is found that the MTGB maintain the flat-topped shape as it propagates. And the uniform properties of the MTGB are closely related to the parameters of fundamental beams and superposition. Both analytical formula derivation and the numerical examples are illustrated. The method is then used to reconfigure the beams of a high power laser diodes stack to form a multi-tilted Gaussian beam shape for a 12°×10° field angle illumination,which is simulated in ASAP software. The shaping method with the proper uniformity and high efficiency is well suitable for laser illuminator in laser active imaging and detecting system.