This application provides a cell measurement method and a communication apparatus. The method may include: A terminal device measures a serving cell by using a wake-up circuit; and when the terminal device has not measured a neighbor cell, the terminal device starts, based on cell quality of the serving cell and a first threshold, to measure the neighbor cell by using a main circuit; or when the terminal device has measured the neighbor cell, the terminal device stops, based on the cell quality of the serving cell and a second threshold, measuring the neighbor cell by using the main circuit, where the first threshold and the second threshold are different.