A method for random access includes that: a terminal device acquires an association between a preamble resource and a physical uplink shared channel (PUSCH) resource; and the terminal device determines, according to the association, a preamble resource and a PUSCH resource used for the terminal device to perform random access. A method for random access includes that: a network device receives a preamble transmitted by a terminal device on a preamble resource, the preamble resource having an association with a physical uplink shared channel (PUSCH) resource; and the network device determines, according to the association between the preamble resource and the PUSCH resource, a PUSCH resource for transmitting a PUSCH by the terminal device. A terminal device and a network device are also provided.