The features of Moire fringe generated by overlapping a circular and a linear grating are studied. Given that the pitch of circular grating is a and that of linear grating is P, the shapes of the Moire fringe that they form are hyperbola, parabola, and ellipse when a > P, a = P, and a < P, respectively. As the pitches of these two gratings become close to each other, the magnification of the Moire fringe is over 100, which is useful for the measurement of small displacement. This letter also discusses how the fill factor influences Moire fringe visibility.