ferroelectric ceramics has been measured. It is found that the polarization fatigue in BST ceramics can be divided into three stages. The first stage when reversal number
N
is between 10
5
to 10
6
is dominated by aged effects. In the second stage where
N
is from 10
6
to10
8
fatigue effect appears. In the third stage when
N
is larger than 10
8
the sample is almost totally fatigued and can not be considered as a ferroelectrics.