The nanometric internal structure of polymeric fibres is fundamental for their mechanical properties. Two-dimensional small angle neutron scattering patterns were collected to obtain structural parameters of the elementary fibrils in regenerated cellulose fibres prepared by various fibre spinning technologies. Scattering features were fitted to model functions to derive parameters such as elementary fibril radius, long period of the repeating units of crystal and amorphous phase along the fibre axis, degree of orientation, and ellipticity. The correlation between structural parameters and the mechanical properties was studied for the fibres of different existing spinning processes and for the high-strength fibres. Former group showed high correlation with mechanical properties. The latter group showed generally lower correlation, but showed relatively high correlation with the long period. These structural parameters provide a basis for understanding the structure-property relationship of regenerated cellulose fibres as function of spinning types and conditions for further optimization. Display omitted •Scattering length density of amorphous cellulose was modulated by solvation.•Four-point pattern were observed for Lyocell-based fibres.•Nanostructural parameters were evaluated from small angle neutron scattering.•Divergent nanostructures of regenerated cellulose fibres by spinning types.•Correlation between structural parameters and tensile properties were discussed.