The utility model relates to a supplementary mounting platform of portable lift of aircraft APU relates to the supplementary installation of the portable lift of aircraft APU, belongs to the aviationequipment technological field. It includes work platform, elevating system and running gear, work platform sets up on elevating system, and work platform comprises support and workstation, and the support is used for fixed aircraft APU, elevating system is located between work platform and the running gear for drive work platform's rising and decline, and be equipped with scissor lift, lift driving motor and reduction gear, lift driving motor is connected with scissor lift with the reduction gear, running gear is located work platform's bottom, is equipped with the wheel, driving motor and power and automobile body travel, be provided with the wheel on the automobile body. The utility model discloses realize APU's work such as installation, dismantlement and transport, improve the installation effectiveness of complete machine.