Disclosed are methods and devices for data transmission in a wireless local area network. According to the embodiments of the present application, through transmitting by a terminal a first data frame to an access device, where the first data frame includes indication information and uplink data and the indication information is used to indicate a power save poll and uplink data transmission, the terminal can receive a second data frame which is transmitted by the access device according to the first data frame, where the second data frame includes response information of the power save poll indicated by the indication information. Since the first data frame carrying the uplink data indicates the power save poll simultaneously, downlink data from the access device can be inquired or requested at the same time of transmitting the uplink data, so that data transmission efficiency is improved.