Abstract: Positional offsets of the reference microphone (REF) and the microphone to be tested (DUT) are considered to be an important component causing measurement uncertainty in the free-field comparison method. To assess the effect of positional offset on the sensitivity and frequency response calibration results, this paper quantitatively analyzes the effect of positional offset on the sensitivity level at each frequency by controlling the horizontal and axial offsets of the REF and DUT during the calibration process. A least-squares fit of the calibration results of the sensitivity level to the displacement offset is performed in the frequency range of 250 Hz to 20 kHz, and corresponding fit curves are provided. Statistical tests were also carried out on the fitting results. According to the slopes of the fitted curves and the significance levels obtained from the tests, it is shown that with increasing frequency, the influence of horizontal offset on the calibration results of the sensitivity level increases significantly, reaching a maximum slope of 0.016 dB/mm at 20 kHz. The effects of axial deviation on the sensitivity level vary at different frequency points, with some frequencies being insensitive to axial offset.