This paper investigates the influence of vacuum annealing temperature on the microstructure, mechanical properties and electrical resistivity of Mg-3Al-1Zn rapid solidification (RS) magnesium ribbons. The results indicate that when the annealing temperature is increased, the grain size of the ribbons is dramatically reduced from 10 to 1 μm. The highest break stress and micro-hardness is obtained at 673 K. These effects are ascribed to the dispersion strengthening caused by the high amount of fine nanoparticles distributed in the material. Electrical resistivity-temperature (ρ-T) curves have been used to provide useful information about the effects of the annealing temperature on the grain size, grain orientation and crystal structure of the ribbons. In this way, a new lightweight electric wire or connection cable line could be produced which would have good electromagnetic interference (EMI).