The Normal Zone Propagation Velocity (NZPV) of a double-layer second generation (2G) high temperature superconducting (HTS) wire manufactured by American Superconductor has been measured by electrical and thermal methods, and the results have been compared and discussed. The NZPV values determined by the voltage traces are ranging from 3.8 mm/s at 0.4 Ic to 19.2 mm/s at 0.9 Ic; while from 5.9 mm/s to 18.3 mm/s by the temperature traces. NZPV determined by these two approaches agrees well with each other. Also, NZPV of double-layer YBCO tape is close to that of conventional single-layer superconducting tape.