Abstract: In this paper, we first analyse by the geometric optics method the relation of angular sensitivity and deviation distance sensitivity with the magnification m and tilt angle β respectively. Then the changes of near-field phase and far-field intensity, which were led to by the tilt of a single mirror and two mirrors with different deviated direction respectively, are computed and analysed by C-6 code. The computational results indicate that the tilt of mirrors really lead to the near field phase changing from uniform to nonuniform distribution and the laser beam quality from high to low.

Key words: virtual confocal unstable resonator with strip mirrors of cylindrical surfaces, mirrors tilt, near-filed phase, far-field intensity