Abstract: The generalized fractal dimension is introduced to study fractal distribution of seismicity time in this paper.On the basis of generalized fractal dimension D_o(ε) before and after Haicheng, Lancang-Gengma and Liyang earthquakes, it is found that a range of timescale is 2-16 days,the D_o(ε) change can reflect an inhomogeneity of seismic temporal distribution in the seismogenic process of large earthquakes,showing the precursory feature that the fractal dimension drops before the earthquakdes.The scale range of efficient change of D_o(ε) has some relation to regional seismicity.