We derive microscopically the Ginzburg-Landau equations of a d-wave su
perconductor. The structure of a single vortex in such a superconducto
r is determined by solving these equations. The mast interesting featu
re of the vortex structure is the opposite winding s-wave component in
duced near the vortex core. Far away from the center of the vortex cor
e, the winding of s-wave component becomes more complicated and the ma
gnitude shows strong anisotropy.