A light-emitting device driven by an inertial power includes an inertial module, a magnetic element, a magnetic-conductive element, at least one wire, and a light-emitting module. Under an inertial effect, the inertial module drives the magnetic element to rotate, such that a magnetic field generated by the magnetic-conductive element changes due to the rotation of the magnetic element. Moreover, the wire wound around the magnetic-conductive element generates a drive current in response to the changing of the magnetic field, so as to drive the light-emitting module to emit a light. As such, the magnetic field is changed under an inertial power, so as to generate a drive current for driving the light-emitting module, thereby achieving, a renewable energy source, environmental protection, and power-saving purposes.