On winding machine, the main component that has the largest effect on productivity and quality of winded Yarn is the Yarn clearer. Its purpose is to eliminate defects on the Yarns and increase yarn eveness. Studying some technology parameters of the Yarn clearer on the winding machine and its effect on the Yarn strength will help select the correct parameters for the Yarn clearer during the winding process. This article shows that when set changing parameters for neps, thick, thin points on yarn clearer are changed, yarn strength follows this rule: the wider the setting, the more reductive the yarn strength and the tighter the setting, the less reductive the yarn strength. Yarn strength after winding with changed parameters can reduce from 0.6 percent to 14.5 percent in comparision with pre-winding yarn strength.