Provided are a phase detection method and apparatus for a clock signal, and a communication device. A clock signal of a clock to be detected is sampled according to sampling periods set by a sampling clock; a phase angle value corresponding to a sampled clock signal in a current sampling period is obtained according to a mapping relationship between sampled signals and phase angle values; a phase difference corresponding to the current sampling period is subtracted from the phase angle value to obtain an initial phase value of the clock to be detected in the current sampling period, wherein the phase difference is a phase difference between the clock to be detected and the sampling clock in the current sampling period; and after the sampling ends, a final phase value of the clock to be detected is obtained according to initial phase values obtained in respective sampling periods.