Embodiments of this application relate to the field of communications technologies, and disclose an EMF strength control method and a communication apparatus, so that a size of a grid in an EMF strength monitoring process can be adaptively adjusted, thereby reducing processing pressure of a network device while improving EMF strength control precision. A specific solution is as follows: The network device obtains EMF strength of each grid in a first grid group. The first grid group includes M grids obtained by dividing a signal coverage area of the network device, and M is an integer greater than 1. The network device determines a second grid group based on EMF strength of the M grids. The second grid group includes at least a first grid and a second grid, a coverage area of the first grid is greater than that of the second grid, and EMF strength of the first grid is less than EMF strength of the second grid. The network device monitors EMF strength of a coverage area of the second grid group based on the second grid group, to adjust the EMF strength of the coverage area of the second grid group.