The hydrothermally-synthesized barium titanate (BaTiO₃) nanofibers are mechanically milled and used to for the piezocatalytic RhB dye decomposition. It is found that the mechanical milling can improve the piezocatalytic performance of BaTiO₃ nanofibers. With the increasing of the milling time from 0 to 120 min, the RhB dye decomposition ratio of BaTiO₃ nanofibers first increases and then decreases. When the milling time is 30 min, for the 20 min vibration time, the RhB decomposition ratio of BaTiO₃ is 94%, which is much higher than that (~65%) of the unmilled BaTiO₃. On one hand, the enhancement in piezocatalysis of BaTiO₃ may be originated from the exposure of active sites due to the increasement of the specific surface area after the mechanical milling. On the other hand, it is also found that the ferroelectric polarization strength of BaTiO₃ nanofibers obviously increases after the mechanical milling, which is helpful to reduce the recombination of these positive and negative carriers in the catalytic process, resulting in the enhanced piezocatalysis performance. The mechanical milling provides a convenient, fast, and effective method for improving the piezocatalytic activity of BaTiO₃ nanofibers.