Up to now, in most network cable factories, the detection of twistedpair pitch is still completed by manual sampling test. In china, most of the existing twistedpair pitch detection methods based on machine vision are remained in laboratory stage. In real production line, the detection results of these methods cannot satisfy the actual industrial detection requirements. Aiming at this problem, a realtime detection method is proposed for twistedpair pitch based on edge reconstruction. The method firstly extracts the edge data of the twistedpair with fast twisted pair edge detection method, and then reconstructs the twisted pair edge with Hammerstein model and hybrid particle swarm optimization (HPSO) algorithm. By this way, the method can filter out noise and obtain smooth twistedpair edge curve with precise twisted point position. On this basis, the twistedpair pitch data can be obtained finally through finding the twisted point positions. Through testing, the method can detect 125 m cable product per minute, the detection error is controlled between -161%~158%, all the specifications can meet the requirements of industrial realtime detection, and this method has high practical application value.