Provided are an information transmission method, a terminal device and a network device. The method includes that: a terminal device acquires a first sequence, the first sequence being used for determining a sequence carrying feedback information for downlink data; the terminal device determines target feedback information for target downlink data sent by a network device according to the target downlink data; the terminal device determines a second sequence carrying the target feedback information according to the first sequence; and the terminal device sends the second sequence to the network device. Therefore, the terminal device may efficiently acquire a sequence configured to carry uplink control information.