The work aims to study the effects of high-speed oblique cutting parameters on chip morphology and evolution law of high-strength aluminum alloy, and explore the internal mechanism of chip morphology transformation, so as to provide theoretical basis for extending tool life and improving processing technology. In this paper, a three-dimensional numerical model of 7N01 aluminum alloy high-speed oblique cutting was established based on the general finite element software. The cutting experiments were carried out with machining center and three-dimensional dynamometer. The chip morphology was characterized by metallographic microscope and scanning electron microscope. Combined with the finite element simulation results, the chip evolution mechanism was explored. The results showed that, under the condition of 15° blade inclination, 2 mm cutting depth and 0.9 mm/z feed, when cutting speed was lower than 900 m/min, there was obvious tearing or serrated edge phenomenon on the side contacting with the tip first in the width direction of chip. At this time, the cutting force wave was violent. Combined with the microstructure and finite element analysis, it was found that the stress and temperature level of this side was significantly higher than that of the other side, and the cyclic tension compression plastic deformation was the main factor leading to chip serrated burr. When the cutting speed was higher than 700 m/min, the thermal softening effect was enhanced, and the thermoplastic shear instability caused by adiabatic shear played a leading role. The serrated edge gradually disappeared, and an obvious adiabatic shear band appeared along the chip thickness direction, that was, serrated chips were formed, and the degree of serration increased with the increase of cutting speed. In oblique cutting, chip shape will change with the change of cutting speed. The thermal mechanical coupling is the main reason for chip evolution. The two kinds of serrated chips will bring the fluctuation of cutting force and affect the surface quality, which should be avoided as far as possible in the actual cutting process.