The invention discloses a clock generator with ultralow power consumption. The clock generator comprises a broadband annular oscillator, a self-correction unit, a frequency detection unit and a frequency divider, wherein the broadband annular oscillator which consists of a phase inverter unit and a decoding and biasing circuit supplies a linearly changed clock signal with a wide range; the self-correction unit which consists of a rising edge detector, a rising edge counter, a reference frequency divider, a state machine, a reference counter, a comparator and a parameter configuration unit is used for correcting change of an output clock of the broadband annular oscillator, which is caused by a process, temperature and voltage; the frequency detection unit which consists of a frequency detection enabling door, a frequency doubler, a detection counter, a parameter configuration unit and a comparator is used for detecting the output clock; and when the frequency offset of the output clock is greater than a preset value, the self-correction unit is started. The clock generator can adjust the frequency of the output clock according to a requirement, has a simple structure, ultralow power consumption, a small area and high reliability, is easy to integrate, and can be widely applied to communication systems, and the shortcoming of the frequency offset of the clock generator is overcome.