Abstract: The magnetic polarity reversal polarity reversal record is often illustrated by means of a column with black and white intervals depicting the two polarity. The cumulative polarity bias curve is introduced here as an alternative method to demonstrate the record of geomagnetic polarity reversals. This new methods, which is obtained by compounding the length of magnetic polarity bias of the magnetic field over any period of time, as well as the hysteretic properties of the field. It also serves as an efficient means for the evaluation of geodynamo models. An example is presented in this paper to demonstrate how the cumulative polarity bias can be used to evaluate the effects of variations in both the dimensionless parameters and the signal/noise ratio on the polarity bias, length and frequency of polarity zones.