The tensile properties and electrical conductivity of 7A55 aluminum alloys at different states during RRA conventional treatment and RRA continuous treatment were tested and the microstructure evolution in the two periods was observed by TEM. The results show that either after conventional RRA treatment or after continuous RRA treatment, the alloy is composed of a large number of metstable η′ phase precipitates and a few η phase precipitates in grains; η phase precipitates are coarsened seriously and PFZ (precipitate free zone) appears at the grain boundaries; the electrical conductivity is greatly increased during the retrogression step. In addition, after the first step treatment without air cooling, heated to the retrogression temperature at a proper heating rate, the 7A55 alloy can obtain the strength near the first step aging levels together with the electrical conductivity of 38.1%IACS in continuous RRA treatment.