An uplink control information transmission method and a device. The method includes obtaining a first modulation and coding scheme offset value used to multiplex first uplink control information on a physical uplink shared channel, where the first modulation and coding scheme offset value is less than 1, and mapping, according to the first modulation and coding scheme offset value, the first uplink control information to a resource for the physical uplink shared channel, to transmit the first uplink control information to a network device using the resource for the physical uplink shared channel.