A method for measuring a pattern of a substrate is provided to obtain a two-dimensional image by using an array sensor for receiving slit beams according to a reflective angle equivalent to an incident angle in each of reflected slit beams. A multi-slit beam penetrate a lens(S110). The multiple slit beam is irradiated onto a surface of an inspection region according to the predetermined incident angle(S120). The reflected multi-slit beam penetrates the lens according to a reflective angle equivalent to the incident angle(S130). An array sensor receives the reflected multi-slit beam(S140). The amount of the received multi-slit beam in each of pixels is measured(S150). A two-dimensional image data is obtained in the inspection region by using the amount of the received multi-slit beam(S160). A pattern structure of the inspection region is measured by using the two-dimensional image data(S170).
