The invention relates to an 
arc length parameter curve 
processing track generation method of a free curved surface. The method comprises following steps of smooth and continuous characteristic curve 
processing track extraction, given precision parameter curve 
processing track generation and processing track 
arc length parameterization. In the step (1), processing tracks generated by computer aidedmanufacturing 
software (
CAM) are classified according to 
arc length characteristics; and discrete free curve processing tracks with smooth and continuous characteristics are extracted; in the step (2), fitting is performed on the extracted discrete free curve processing tracks under the given precision, so parameter curve processing tracks meeting a 
geometric representation precision requirementare obtained; and in the step (3), by use of the method of continuous iteration arc length re-parameterization, arc length re-parameterization is performed on the parameter curves obtained in the step(2), and finally, the arc length parameter curve free curved face processing track is obtained. According to the invention, the difficulty level in real-time interpolation and speed planning in freecurved face processing is reduced; and smoothness and processing precision in the processing process are improved.