A resistive memory device and a reliability enhancement method thereof are provided. The reliability enhancement method includes the following steps. A forming operation is performed on a plurality of memory cells. The formed memory cells are read to respectively obtain a plurality of formed currents. A reference current is set according to a statistic value of the formed currents. A setting operation is performed on the memory cells. A ratio between a set current of each of the memory cells and the reference current is calculated, and a physical status of each of the memory cells is judged according to the ratio. It is determined whether to perform a fix operation of each of the memory cells or not according to physical status.