Provided is a method for magnifying an image by interpolation. The method including: a) setting m.times.m local windows and calculating a direction of each m.times.m local window; b) when a linear direction exists in an m.times.m local window, considering an edge exists; c) when a linear direction does not exist in the m.times.m local window, dividing the m.times.m local window into m/2.times.m/2 sub windows and calculating directions of the m/2.times.m/2 sub windows; d) when the directions of the m/2.times.m/2 sub windows exists toward the center of the m.times.m local window, considering a corner exists in the m.times.m local window; and e) selecting pixels located in a virtual line that goes along in the linear direction or in the directions to calculate a new pixel value by using the pixels.