A data sending method performed by a sending device, wherein the method comprises the steps of: • obtaining (S 701) a target medium access control protocol data unit, MPDU, wherein the target MPDU is obtained by performing encapsulation processing on an IP data packet of a specified service, and the sending device and a receiving device are connected through wireless fidelity, Wi-Fi; • obtaining a retransmission rate between the sending device and the receiving device, wherein the retransmission rate is determined based on a quantity of already retransmitted MPDUs sent to the receiving device through the Wi-Fi connection in a unit time and a total quantity of MPDUs already sent to the receiving device through the Wi-Fi connection in the unit time that are obtained through statistics collection; • if the retransmission rate is greater than a preset retransmission threshold: ∘ triggering an execution of generating at least one backup MPDU of the target MPDU, and generating (S 703) the at least one backup MPDU of the target MPDU, wherein, for generating the at least one backup MPDU of the target MPDU, the following method steps are performed: ▪ determining a quantity of backup MPDUs based on the retransmission rate and the retransmission threshold, wherein the quantity of backup MPDUs is a positive integer; and ▪ performing replication processing on the target MPDU based on the quantity of backup MPDUs, to generate the at least one backup MPDU, wherein a number of the generated at least one backup MPDU is equal to the determined quantity of backup MPDUs, and ∘ after having generated the at least one backup MPDU, sending (S 704) the target MPDU and the at least one backup MPDU to the receiving device through the Wi-Fi connection; • if the retransmission rate is not greater than the preset retransmission threshold, sending the target MPDU to the receiving device through the Wi-Fi connection. • obtaining (S 701) a target medium access control protocol data unit, MPDU, wherein the target MPDU is obtained by performing encapsulation processing on an IP data packet of a specified service, and the sending device and a receiving device are connected through wireless fidelity, Wi-Fi; • obtaining a retransmission rate between the sending device and the receiving device, wherein the retransmission rate is determined based on a quantity of already retransmitted MPDUs sent to the receiving device through the Wi-Fi connection in a unit time and a total quantity of MPDUs already sent to the receiving device through the Wi-Fi connection in the unit time that are obtained through statistics collection; • if the retransmission rate is greater than a preset retransmission threshold: ∘ triggering an execution of generating at least one backup MPDU of the target MPDU, and generating (S 703) the at least one backup MPDU of the target MPDU, wherein, for generating the at least one backup MPDU of the target MPDU, the following method steps are performed: ▪ determining a quantity of backup MPDUs based on the retransmission rate and the retransmission threshold, wherein the quantity of backup MPDUs is a positive integer; and ▪ performing replication processing on the target MPDU based on the quantity of backup MPDUs, to generate the at least one backup MPDU, wherein a number of the generated at least one backup MPDU is equal to the determined quantity of backup MPDUs, and ∘ after having generated the at least one backup MPDU, sending (S 704) the target MPDU and the at least one backup MPDU to the receiving device through the Wi-Fi connection; ∘ triggering an execution of generating at least one backup MPDU of the target MPDU, and generating (S 703) the at least one backup MPDU of the target MPDU, wherein, for generating the at least one backup MPDU of the target MPDU, the following method steps are performed: ▪ determining a quantity of backup MPDUs based on the retransmission rate and the retransmission threshold, wherein the quantity of backup MPDUs is a positive integer; and ▪ performing replication processing on the target MPDU based on the quantity of backup MPDUs, to generate the at least one backup MPDU, wherein a number of the generated at least one backup MPDU is equal to the determined quantity of backup MPDUs, and ▪ determining a quantity of backup MPDUs based on the retransmission rate and the retransmission threshold, wherein the quantity of backup MPDUs is a positive integer; and ▪ performing replication processing on the target MPDU based on the quantity of backup MPDUs, to generate the at least one backup MPDU, wherein a number of the generated at least one backup MPDU is equal to the determined quantity of backup MPDUs, and ∘ after having generated the at least one backup MPDU, sending (S 704) the target MPDU and the at least one backup MPDU to the receiving device through the Wi-Fi connection; • if the retransmission rate is not greater than the preset retransmission threshold, sending the target MPDU to the receiving device through the Wi-Fi connection.