An automobile automatic transmission axle assembly: A power input shaft extends into a transmission compartment; the power input shaft in the transmission compartment is provided with a transmission mechanism; the transmission mechanism comprises a transmission sliding sleeve assembly, modified isolators, gear-position sun gears, planet gears, a planet carrier and gear rings; the gear-position sun gears, planet gears and gear rings constitute a mechanism having a fixed transmission ratio; the transmission sliding sleeve assembly fits the modified isolators. The automobile automatic transmission axle assembly realizes an integrated automatic transmission axle for electric vehicle.