Abstract: A generator structure for a bicycle hub is provided with a generator on an axle in a hub housing. The generator is provided with a magnet group and two opposite yoke iron groups on an outer periphery of a coil unit. The magnet group is formed by arranging plural magnets into an annular shape, and the respective magnets are made of sintered NdFeB and have an N pole at one side thereof and an S pole at the other side thereof. The N poles and the S poles of the magnets are alternately arranged around the magnet group. The outer periphery of each of the yoke iron groups is provided with claws, and the two yoke iron groups are oppositely combined together from both sides of the coil in such a manner that the claws of the yoke iron groups are located on the outer periphery of the coil unit.