A delay lock loop (DLL) including a voltage control delay line (VCDL), a phase frequency detecting loop (PFD loop), and a phase limiting loop is provided. The VCDL generates an output clock signal according to a DC voltage signal, wherein the VCDL delays an input clock signal by a specific period so as to generate the output clock signal. The PFD loop generates the DC voltage signal according to the phase difference of the input clock signal and the output clock signal and is controlled by an initiation signal. The phase limiting loop limits the delay of the output clock signal to be less than a delay time and generates the initiation signal to enable the PFD loop. Furthermore, a clock signal generating method is also provided.