Abstract: Dispersion properties play a key role in high power supercontinuum generation in large mode area Yb-doped double-clad fiber. In this paper, an improved ultra-broadband and high resolution dispersion measurement system, based on a Mach-Zehnder interferometer and supercontinuum, was set up. The test arm of the interferometer was inserted with the fiber under test, and the reference arm of adjustable optical path length was tuned by a computer-controlled stepper motor with high resolution. The accurate dispersion characteristics of large mode area Yb-doped double-clad fiber was measured with a very short length of 27.2 cm. A series of interferometric fringes of different wavelengths, over a wide spectral range from 700 nm to 1 600 nm, were recorded to calculate the dispersion curve. Numerical calculation of the dispersion by finite element method was also made. The test results are in great agreement with numerical calculation, which shows good performance of the method and experimental system.