Based on the need of calibrating the liquid level sensor, dynamic calibration device was designed and developed for liquid level sensor which applied to capacitive sensors (measuring range is 1 800 mm, and limiting error is ±2 mm) in both normal and low temperature conditions. The principle of homogeneous coordinate transformation was used to establish geometric error model for the calibration device, which mainly contained the rail straightness error, positioning error, spatial angle error of each chain and level fluctuation error, and other aspects. Moreover, the uncertainty of calibration device was evaluated. The results show that the expanded uncertainty is U=0.53 mm（k=2）, which meets the specifications of calibration accuracy of the cryogenic liquid level sensor.