The invention provides a system and a method for the multi-sensor-based on-line multi-dimension measurement of special-shaped shaft-type workpieces, relating to the technical field of motion control, image processing, on-line detection and the like. The system comprises an automatic clamping module for workpieces, an automatic measuring module and a signal processing module and is characterized in that the automatic clamping module and the automatic measuring module are located between two transmission belts, wherein the automatic clamping module is used for automatically clamping the workpieces, so as to achieve the on-line detection of workpieces; the automatic measuring module is used for achieving the multi-dimension measurement of workpieces through the cooperative work of sensors; the signal processing module is used for carrying out the data information transmission with the automatic clamping module and the automatic measuring module; and the motion controlling program, image processing program and data analyzing program for controlling the automatic clamping module and the automatic measuring module are installed in the industrial personal computer of the signal processing module. The method comprises the following steps: carrying out the length measurement on the shaft-type workpieces through the motion and cooperative work of eddy-current sensors and lead screws; and carrying out the high-precision axial multi-dimension measurement on the special-shaped shaft-type workpieces through the multi-sensor cooperative work.