A transmit power adjustment method, comprising: calculating, by a wireless access point device that can serve as a hotspot, channel state information of a channel between the wireless access point device and a station device within a particular time range, wherein the channel state information is used to indicate a frame error rate of data transmission on the channel within the particular time range, wherein the frame error rate represents a probability of failing to send data in a process of data transmission between the wireless access point device and the station device; comparing, by the wireless access point device, the channel state information with pre-obtained reference channel state information, and adjusting, according to a result of the comparison, a transmit power currently used by the wireless access point device; and sending, by the wireless access point device to the station device by using a transmit power after the adjustment, a message carrying data; wherein the calculating, by a wireless access point device, channel state information of a channel between the wireless access point device and a station device within a particular time range comprises: receiving, by the wireless access point device, an acknowledgement, ACK, frame returned by the station device in response to a message frame that is sent by the wireless access point device on the channel; calculating, by the wireless access point device, the frame error rate of the channel within the particular time range according to a quantity of message frames that are sent by the wireless access point device to the station device on the channel within the particular time range and a quantity of acknowledgement ACK frames received within the particular time range; and using, by the wireless access point device, the frame error rate as the channel state information of the channel. calculating, by a wireless access point device that can serve as a hotspot, channel state information of a channel between the wireless access point device and a station device within a particular time range, wherein the channel state information is used to indicate a frame error rate of data transmission on the channel within the particular time range, wherein the frame error rate represents a probability of failing to send data in a process of data transmission between the wireless access point device and the station device; comparing, by the wireless access point device, the channel state information with pre-obtained reference channel state information, and adjusting, according to a result of the comparison, a transmit power currently used by the wireless access point device; and sending, by the wireless access point device to the station device by using a transmit power after the adjustment, a message carrying data; wherein the calculating, by a wireless access point device, channel state information of a channel between the wireless access point device and a station device within a particular time range comprises: receiving, by the wireless access point device, an acknowledgement, ACK, frame returned by the station device in response to a message frame that is sent by the wireless access point device on the channel; calculating, by the wireless access point device, the frame error rate of the channel within the particular time range according to a quantity of message frames that are sent by the wireless access point device to the station device on the channel within the particular time range and a quantity of acknowledgement ACK frames received within the particular time range; and using, by the wireless access point device, the frame error rate as the channel state information of the channel. receiving, by the wireless access point device, an acknowledgement, ACK, frame returned by the station device in response to a message frame that is sent by the wireless access point device on the channel; calculating, by the wireless access point device, the frame error rate of the channel within the particular time range according to a quantity of message frames that are sent by the wireless access point device to the station device on the channel within the particular time range and a quantity of acknowledgement ACK frames received within the particular time range; and using, by the wireless access point device, the frame error rate as the channel state information of the channel.