The presentation is a summary of a series of papers~[1-4]
on fragmentation function studies in $e^+e^-$-annihilation at high energies published recently by the SDU group on QCD and hadron physics. After a brief description of the three-dimensional fragmentation functions defined via quark-quark correlator for hadrons with different spins (0, 1/2 and 1) at leading and higher twists, we discuss how to study them in hadron production processes in $e^+e^-$-annihilation at high energies. We first present the general framework to express the cross section in terms of the corresponding structure functions based on the general kinematic analysis then give the parton model results for the differential cross sections and/or different spin asymmetries up to twist-3 in terms of gauge invariant fragmentations. The results can serve as a basis for experimental and phenomenological studies in this reaction.