A time-to-digital converter including N stages of converting circuits, where N≧2, and N is an integer. Each stage of converting circuit includes a first delayer and an arbiter; an output end of the first delayer in each stage of converting circuit outputs a delayed signal of the stage of converting circuit; and the arbiter in each stage of converting circuit receives a sampling clock and the delayed signal of the stage of converting circuit, and compares the sampling clock with the delayed signal to obtain an output signal of the stage of converting circuit. Output signals of the N stages of converting circuits form a non-linear binary number, to indicate a time difference between a clock signal and a reference signal.