AbstractThe stability of high Tc superconducting tape against AC loss was evaluated numerically considering the change of transport current distribution when external transient magnetic fields were applied perpendicular to the tape. The process of the temperature increase and the recovery to the temperature of coolant was predicted, and it was confirmed that the increase of temperature is mainly dependent on the change rate of external fields. The numerical results indicate high Tc superconducting tape is exceedingly stable and the quench cannot occur even in the intense fields conditions.