The invention discloses a garbage-truck intelligent mechanical arm. The garbage-truck intelligent mechanical arm comprises a holding grabbing device, a lifting assembly, a stretchable assembly, an overturning assembly and a central controller. The holding grabbing device comprises a bearing assembly, a holding grabbing assembly and a proximity switch, and the bearing assembly comprises a sliding rod. The lifting assembly comprises a guide rail bracket, a lifting oil cylinder and an overturning arm; an ascending travel switch and a descending travel switch are arranged on the lifting assembly. The stretchable assembly comprises a fixing support and a stretchable arm; a motor and an encoder are installed on the fixing support, and a gear is installed on an output shaft of the motor; a fixing rack engaged with the gear is arranged on the fixing support. The overturning assembly comprises an overturning oil cylinder and an output shaft; an overturning travel switch and a horizontal travel switch are arranged on the overturning assembly. The central controller is connected with the holding grabbing device, the lifting assembly, the stretchable assembly and the overturning assembly. By means of the garbage-truck intelligent mechanical arm, a garbage can can be positioned and caught through the mechanical arm, and manual can hanging and manual can frame leaving are avoided; after the garbage can is preliminarily positioned, follow-up action is automatically and intelligently controlled, and safety and efficiency are achieved.