The invention discloses a lifting mechanism of an electric shovel, which comprises a drum inner sleeve, a transmission side spindle, a first grade sun wheel, a first grade planet wheel pin shaft, a first grade planet wheel, a first grade inner gear ring, a first grade planet carrier, a second grade planet carrier, a second grade planet wheel pin shaft, a second grade inner gear ring, a second grade planet wheel, a second grade sun wheel support, a second grade sun wheel and a fixation side spindle, wherein a first grade speed-reduction transmission mechanism comprises the first sun wheel, the first grade planet wheel, the first grade inner gear ring and the first grade planet carrier; and a second grade speed-reduction transmission mechanism comprises the second grade sun wheel, the second grade planet wheel, the second grade inner gear ring, the second grade planet carrier and the second grade sun wheel support. According to the invention, as the single-motor input is adopted, and the two grades of the speed-reduction transmission mechanisms are installed in the drum inner cavity, the space in the drum is completely utilized; the speed-reduction mechanisms adopt two grades of planet gear wheels to realize transmission, so that the transmission of the planet gear wheel has great transmission ratio; and the lifting mechanism is compact in structure and can greatly reduce the weight of the equipment.