The invention relates to a laser cutting method for a brittle substrate, which comprises the following steps that: a brittle substrate is provided; a first cutting line extending along a first direction at the position adjacent to one edge of the brittle substrate is formed by a laser cutting process; an initiate crack starting from the edge and crossing the first cutting line at the position adjacent to the starting end of the first cutting line on the brittle substrate is formed, and the initial crack extends along a second direction different from the first direction; and a second cutting line extending along the second direction is formed along the initial crack on the brittle substrate by the laser cutting process. The invention also provides a brittle substrate manufactured by the method.