The forming of TC4-ELI thick-walled pipe was studied by using finite element numerical simulation and actual extrusion. The differences and the reasons for the differences were explored in microstructure and mechanical properties of different areas in thick-walled pipes. The results show that during the external temperature and equivalent stress of the pipe are relatively high during the extrusion process. More α grains are elongated along the ED direction, and the elongated α grains grow to a higher degree. Base texture with relatively high strength is generated. However, the internal stress of the pipe is relatively low. The preferred orientation of the grains is not obvious, and only weak {-12-10}<20-21> plate texture is generated. Mechanical properties are affected by the combined effect of grain size and crystallographic orientation. Although the exterior of the pipe has coarse grains, the schmid factor between the axial tensile stress and base texture are small. It causes that the exterior of the pipe has higher strength.