Abstract: The 1.1mm thin disk is pumped by CW 800W high power diode lasers stack.The fast axis of each diode laser is collimated with an aspheric microlens.Two macroscopic lenses are used to focus the light by transforming the fast axis and the slow axis,and a 10mm×7mm spot is achieved in the surface of the thin disk.The pumping light that is not absorbed by the thin disk passes the thin disk again when reflected by the spherical reflector,and high absorbing efficiency is obtained.Up to 800W can be focused on a 10mm×7mm spot with the beam parameter product of 640mm·mrad and 540mm·mrad in the fast and slow axis.The pumping light tested by the CCD camera is nearly the symmetric beam.Its cou pling efficiency is up to 80.5% in the 10mm×7mm spot with the aspheric microlens and two cylinder lenses.