The dynamic radius is one of the main factors contributing to the uncertainty of the precision centrifuge. To study the dynamic radius relation with the acceleration and the influence factors, a measurement system using capacitance detectors, which is mounted off-board, is utilized to measure the dynamic radius at different rotation speeds. Based on an assumption that dynamic radius is Direct Current(DC) component in measured data at a fixed rotation speed, the measured data is analyzed and a change rate of 0.011 482 μm/(m.s-2) for dynamic radius with acceleration is obtained, as well as the turntable shape error. These results could help to modify and compensate the dynamic radius of the precision centrifuge.