A feedback information transmission method in a communications system, comprising: receiving, by user equipment, UE, downlink data from a base station; determining, by the UE, an uplink subframe used for feeding back feedback information corresponding to the downlink data, and determining a first downlink subframe set associated with the uplink subframe, wherein the first downlink subframe set comprises a first subset and a second subset; determining, by the UE, a codebook size of the feedback information, wherein the codebook size is a first codebook size or a second codebook size, the first codebook size is corresponding to a quantity of downlink subframes comprised in the first subset, and the second codebook size is corresponding to a quantity of downlink subframes comprised in the second subset; if the codebook size is the first codebook size, encoding the feedback information according to the first codebook size, to obtain first encoded feedback information, determining a first quantity of symbols according to a first proportion factor, wherein the first quantity of symbols is a quantity of symbols that need to be occupied to map the first encoded feedback information to a physical uplink shared channel, PUSCH; mapping the first encoded feedback information to the PUSCH according to the first quantity of symbols, and sending the first encoded feedback information to the base station in the uplink subframe by using the PUSCH; if the codebook size is the second codebook size, encoding the feedback information according to the second codebook size, to obtain second encoded feedback information, determining a second quantity of symbols according to a second proportion factor, wherein the second quantity of symbols is a quantity of symbols that need to be occupied to map the second encoded feedback information to a physical uplink shared channel, PUSCH; mapping the second encoded feedback information to the PUSCH according to the second quantity of symbols, and sending the second encoded feedback information to the base station in the uplink subframe by using the PUSCH; wherein the first proportion factor and the second proportion factor are independently configured by the base station. receiving, by user equipment, UE, downlink data from a base station; determining, by the UE, an uplink subframe used for feeding back feedback information corresponding to the downlink data, and determining a first downlink subframe set associated with the uplink subframe, wherein the first downlink subframe set comprises a first subset and a second subset; determining, by the UE, a codebook size of the feedback information, wherein the codebook size is a first codebook size or a second codebook size, the first codebook size is corresponding to a quantity of downlink subframes comprised in the first subset, and the second codebook size is corresponding to a quantity of downlink subframes comprised in the second subset; if the codebook size is the first codebook size, encoding the feedback information according to the first codebook size, to obtain first encoded feedback information, determining a first quantity of symbols according to a first proportion factor, wherein the first quantity of symbols is a quantity of symbols that need to be occupied to map the first encoded feedback information to a physical uplink shared channel, PUSCH; mapping the first encoded feedback information to the PUSCH according to the first quantity of symbols, and sending the first encoded feedback information to the base station in the uplink subframe by using the PUSCH; if the codebook size is the second codebook size, encoding the feedback information according to the second codebook size, to obtain second encoded feedback information, determining a second quantity of symbols according to a second proportion factor, wherein the second quantity of symbols is a quantity of symbols that need to be occupied to map the second encoded feedback information to a physical uplink shared channel, PUSCH; mapping the second encoded feedback information to the PUSCH according to the second quantity of symbols, and sending the second encoded feedback information to the base station in the uplink subframe by using the PUSCH; wherein the first proportion factor and the second proportion factor are independently configured by the base station.