The invention discloses a high-sensitivity frequency domain filtering baffle plate Z-scan method for measuring the material nonlinearity, and belongs to the fields of nonlinear photonic material and nonlinear optical information processing. The method of the invention comprises: the focus of a lens forms an image through another lens, and a filtering pinhole is arranged at the point of the image; and a circular diaphragm forms an image through a lens set formed by the above two lenses, and a coaxial circular baffle plate is arranged in the image plane. During the action of pulse laser, a sample moves from side to side near the focus of the lens. Through measuring the non-linear transmittance of an opening, the baffle plate, and the filtering pinhole, the non-linear absorption coefficient and the non-linear refraction coefficient of the material can be determined. The method of the invention is characterized by simple work measurement system optical path, obvious stray light influence filtering effect, high measuring sensitivity, and simple data processing, and can measure non-linear absorption and non-linear refraction at the same time.