1. A multichannel access method comprising:reserving one or more channels for transmission of a current data frame;
obtaining a transmission opportunity (TXOP) of a first reserved channel of the one or more reserved channels;
determining a sending moment of the current data frame in the TXOP and using the sending moment as an ending moment of a preset time segment of the TXOP, wherein a time length of the preset time segment is equal to a point coordination function interframe space (PIFS), a distributed coordination function interframe space (DIFS), an arbitration interframe space (AIFS) or a short interframe space (SIFS);
sensing a non-reserved channel that is not among the one or more reserved channels for transmission in the preset time segment in the TXOP;
if the non-reserved channel is in an idle state for at least the preset time segment, using the non-reserved channel as a second reserved channel; and
when the ending moment of the preset time segment is reached, sending the current data frame on the first reserved channel and the second reserved channel.