So far there is no practical method to determine the duration of geological event before Holocene, and it is necessary to explore the determination means in tectonic field. In this paper, we took the Fuchashan ductile shear zone, Anhui sector of the Tan(cheng)-Lu(jiang) fault as an example to study the duration, and got the following conclusions by the work. The differential stresses of the mylonitized rock, mylonite and ultra-mylonite were 141.17 MPa, 191.88 MPa and 223.31 MPa respectively, the corresponding strain rates were 3.760?10-13 s-1, 7.705?10-13s-1 and 1.087?10-12s-1 respectively. The volumetric factors for the three were 0.7923, 0.6340 and 0.5886 respectively, and the corresponding duration were 2.08?104 a, 1.83?104 a and 1.44?104 a respectively. Checking up by analyzing and comparing varied strain intensities of different samples from the same ductile shear zone, we found that the duration of the sample from marginal position was evidently longer than that from central part. The self-test method might be a new attempt in enhancing the precision as to the situation in case of without available geochemical methods. The systematic discussion about duration determination was revision and summarization of the work ever before, which should benefit for the quantification of tectonic geology and tectono-chronology.