The invention discloses an interferometer with an adjustable dynamic range, which comprises a light source, an illumination system, a beam expansion collimation system, a light splitting system, an imaging system, a PZT precision tiltboard, a Fizeau flat plate, a standard lens, a tested optical element, a mounting and clamping regulation system and a computer control and data processing system. Phase shift related to a spatial position occurs to inclination between tested light and reference light beams among CCD pixels, an angle of inclination of the Fizeau flat plate arranged on the PZT precision tiltboard is controlled by a computer so as to control the spatial frequency of generated carrier frequency interferograms, and various algorithms, such as a Fourier transform-based algorithm, a spatial phase-shift algorithm and the like, are adopted to perform phase resolution. For the carrier frequency interferograms of different kinds of spatial frequency, the algorithms suitable for frequency characteristics of the spatial frequency of the carrier frequency interferograms are adopted to perform optimal phase shift resolution, so that a phase extraction algorithm works in an optimal range to further realize high-precision phase resolution. The interferometer of the invention has the adjustable dynamic range, relatively larger dynamic range, relatively higher measurement precisionand relatively greater application value.