Abstract: In the process of winding,if silk-loop overlapping occurs,the distribution of silk-loop on the bobbin will be uneven,which will result in breakage or entanglement of silk yarn during unwinding.So the phenomena must be avoided.In principle,overlap prevention methods can be classified by the axial and circumferential.In order to prevent silk-loop overlapping,on some equipments the two methods are used simultaneously,making the outfit more complicated but offsetting the overlap prevention effect.Obviously,it is unreasonable.Taking the cop winder of B101 as an example,it has proven by computation that so long as the decimal fraction reasonable,only adopting the circumferential method can achieve good effect of overlap prevention and simplification of the outfit.