A kind of binary optical elements is introduced to implement the transformation of laser beam for high power laser processing. The even sampling Pixellated Dammann grating is adopted to perform the Guassian beam transformation in order to obtain the given output spots. The principle and implementation of the beam transformation technology of pixellated Dammann grating is described with examples of the linear, even, annulus and uneven array. Results show that the output spots have high diffractive efficiency and uniformity. The application of the even and uneven array spot in the laser surface modification is investigated, showing the improvement of the hardness and the wear resistance of the sample surface, and the uniformity of the modified surface.