Multiphase motors inherently have the advantage of strong fault tolerance, so their fault-tolerant control has been paid more and more attention. In the fault-tolerant control strategy based on current optimization method under open-phase faults (OPFs), the current references must be reconstructed to ensure the minimum torque ripple. In this paper, an online optimal fault-tolerant control strategy for asymmetrical multiphase motors (AMMs) with arbitrary open-phase faults and different neutral point configurations is proposed. Simulation demonstrates that it can achieve online current optimization guaranteeing the minimum torque ripple and the minimum copper losses of stator windings in full torque operation range (TOR). Compared with the offline optimization method, there is no need to pre-store look-up tables which are huge with high phase numbers and different open-phase faults, so it can be flexibly applied to all kinds of open-phase faults of AMMs.