Applying self filtering unstable resonator with an antiresonant ring and a convex mirror to a colliding pulse mode locking Nd:YAG laser, we improved the spatial quality of light beam and output stability and obtained the mode locked trains of 50 mj energy and 10 ps pulse duration with times diffraction limit divergence. Meantime, we compared experimentally the properties of two CPM unstable resonators with a filtering aperture and without it.