An electric bicycle power structure includes a motor, a power exchange device and pedal interlocking shafts; and provides power through the motor or the pedaling pedal interlocking shafts, wherein the powerexchange device automatically switches between the motor and the pedal interlocking shafts to accomplish power saving effects. The power exchange device has a planet decelerating mechanism, a clutch and a chain wheel cover. The power exchange device is located between the motor and the pedal interlocking shaft and is capable of directly switching between these power generating devices. A chain is used to impel the gear and wheel at the chain wheel cover, and an existing transmission gear of the bicycle is employed for accomplishing transmission effects, thereby decreasing numbers of parts without changing designs of the bicycle to further reduce production costs.