© 2019 Author(s). In this work, an improved analytical model for the SET switching statistics of HfO 2 memristive device is developed from the cell-based percolation model. The statistical results of the SET emergence point related to the beginning stage during SET process are systematically discussed. Moreover, the deviation from Weibull model in high percentiles region is found to originate from the uneven distribution of defect density. Our improved model exhibits excellent consistency with experimental results in Cu/HfO 2 /Pt device. Besides, we explain the relationship between the parameters of the model and SET resistance. The underlying mechanism of SET process for HfO 2 memristive device is fully illuminated.