Digital sampling technology is widely used in the field of electrical metrology in recent years. Not only the amplitude errors and phase angle errors of two signals need to be determined, but also the linearity errors of sampling at different input voltage need to be calibrate accurately in establishment of the national high frequency ac power standard. In this paper, a method that using inductive voltage divider (IVD) as the reference to calibrate the linearity errors of two channels of digitizer has been proposed. The method achieves accurate measurements of linearity errors of amplitude and phase angle for high-precision digitizer NI 5922 at frequencies up to 100 kHz by developing the 2n:1 IVD which can be self-calibrated. Experimental results show that the digitizer amplitude linearity errors are less than 60 μV/V, phase angle linearity errors are less than 120 μrad at input voltage from 0.004 V to 1.024 V.