An Ethernet communication method, comprising: sending, by a first device, a time parameter to a second device, wherein the time parameter comprises a parameter of at least one of the following duration: duration of a quiet state, duration of a refresh state, or total duration, and the total duration is total duration of the quiet state and the refresh state; and adjusting, by the first device, state duration in a low power idle, LPI mode of Energy-Efficient Ethernet, based on the time parameter, wherein the sending, by a first device, a time parameter to a second device comprises: either sending, by the first device, the time parameter to the second device in a refresh state in the LPI mode; wherein the LPI mode comprises at least one period, and a quiet state and a refresh state exist in each period; and an effective period of the time parameter is a current period, a next period of the current period, N periods following the current period, or an M th period following the current period in the LPI mode, wherein N and M are integers greater than or equal to 2, or sending, by the first device, the time parameter to the second device in an active state; wherein the LPI mode comprises at least one period, and a quiet state and a refresh state exist in each period; and an effective period of the time parameter is I periods that are in the LPI mode and that are after the active state, or is a J th period that is in the LPI mode and that is after the active state, wherein I and J are integers greater than or equal to 1. sending, by a first device, a time parameter to a second device, wherein the time parameter comprises a parameter of at least one of the following duration: duration of a quiet state, duration of a refresh state, or total duration, and the total duration is total duration of the quiet state and the refresh state; and adjusting, by the first device, state duration in a low power idle, LPI mode of Energy-Efficient Ethernet, based on the time parameter, wherein the sending, by a first device, a time parameter to a second device comprises: either sending, by the first device, the time parameter to the second device in a refresh state in the LPI mode; wherein the LPI mode comprises at least one period, and a quiet state and a refresh state exist in each period; and an effective period of the time parameter is a current period, a next period of the current period, N periods following the current period, or an M th period following the current period in the LPI mode, wherein N and M are integers greater than or equal to 2, or sending, by the first device, the time parameter to the second device in an active state; wherein the LPI mode comprises at least one period, and a quiet state and a refresh state exist in each period; and an effective period of the time parameter is I periods that are in the LPI mode and that are after the active state, or is a J th period that is in the LPI mode and that is after the active state, wherein I and J are integers greater than or equal to 1. sending, by the first device, the time parameter to the second device in a refresh state in the LPI mode; wherein the LPI mode comprises at least one period, and a quiet state and a refresh state exist in each period; and an effective period of the time parameter is a current period, a next period of the current period, N periods following the current period, or an M th period following the current period in the LPI mode, wherein N and M are integers greater than or equal to 2, or sending, by the first device, the time parameter to the second device in an active state; wherein the LPI mode comprises at least one period, and a quiet state and a refresh state exist in each period; and an effective period of the time parameter is I periods that are in the LPI mode and that are after the active state, or is a J th period that is in the LPI mode and that is after the active state, wherein I and J are integers greater than or equal to 1.