Abstract: In this paper TC4 （Ti-6Al-4V） chip has been observed on its photomicrographs and analyzed by AES. And It is believed to be the first that a dynamic investigation on the titanium alloy chip-formation has been made with the aid of high speed movie camera type E-10, digital storage o-scilloscope DSS-6521 and piezoelectric dynamometer kistler 9257A; and chip forming pro'cess with the instantaneous fluctuation of cutting force has been photographed synchronously in the same frame. Thus, it can be concluded that the effect .. of the chemical affinity of titanium on chip segmentation is insignificant periodic gross inhomogeneous deformation occurs in the titanium alloy chip; and the localized concentration shear caused by adiabatic cutting process plays an important role in chip segmentation.