The invention relates to an automatic workpiece loading assembly based on robot workpiece pickup, and belongs to the field of automobile parts. The automatic workpiece loading assembly based on robot workpiece pickup comprises a sliding table base, a manual workpiece loading device arranged at one end of the sliding table base, a robot workpiece grabbing device arranged at the other end of the sliding table base, and a sliding table walking car positioned on the position of the robot workpiece grabbing device, wherein the sliding table base comprises guide rails arranged at the two ends of the sliding table base, a sliding table gear rack arranged on the middle part of the sliding table base, an assembly switch arranged at one end of the sliding table base, and a sliding table guide limiting assembly arranged at the other end of the sliding table base. The automatic workpiece loading assembly based on robot workpiece pickup can realize rapid transportation of products among different assembly lines, saves labor power and time and improves efficiency. Repeated positioning precision for transportation is realized by virtue of mechanical locking and positioning, so that the automatic control is simplified, and the cost is saved; the mechanical structure is simple, and high-precision transportation at different distances can be realized by changing the lengths of the guide rails and the length of a transmission rack; and the repeated positioning precision is high and the transmission speed is high, so that the automatic workpiece loading assembly can be cooperated with automatic equipment such as a robot and the like very well in work.