A control information transmission method performed by a network side device, wherein the method comprises: when a first resource and a second resource that are configured by the network side device for a terminal device are located in a same subframe, receiving, on one of the first resource and the second resource, a modulation symbol sent by the terminal device; and determining, by the network side device based on the resource used to receive the modulation symbol and a preset mapping relationship between bit combinations and modulation symbols, a bit combination corresponding to the received modulation symbol, wherein in the mapping relationship, the bit combination comprises a scheduling request SR bit and an acknowledgment ACK/negative acknowledgment NACK bit; each bit combination corresponds to one modulation symbol needing to be sent on the first resource or corresponds to one modulation symbol needing to be sent on the second resource; and in bit combinations corresponding to modulation symbols sent on at least one of the first resource and the second resource, SR bits in at least two bit combinations are different, and ACK/NACK bits in at least two bit combinations are different; characterized in that in the mapping relationship, each bit combination corresponds to one first-type modulation symbol that needs to be sent on the first resource and one second-type modulation symbol that needs to be sent on the second resource, and a value that is of one modulation symbol in the first-type modulation symbol and the second-type modulation symbol and that corresponds to a value of the bit combination is 0, and a value that is of the other modulation symbol and that corresponds to the value of the bit combination is not 0; and correspondingly, the receiving, on one of the first resource and the second resource, a modulation symbol sent by the terminal device comprises: receiving, on the first resource, a first-type modulation symbol whose value is not 0 and that is sent by the terminal device, or receiving, on the second resource, a second-type modulation symbol whose value is not 0 and that is sent by the terminal device. when a first resource and a second resource that are configured by the network side device for a terminal device are located in a same subframe, receiving, on one of the first resource and the second resource, a modulation symbol sent by the terminal device; and determining, by the network side device based on the resource used to receive the modulation symbol and a preset mapping relationship between bit combinations and modulation symbols, a bit combination corresponding to the received modulation symbol, wherein in the mapping relationship, the bit combination comprises a scheduling request SR bit and an acknowledgment ACK/negative acknowledgment NACK bit; each bit combination corresponds to one modulation symbol needing to be sent on the first resource or corresponds to one modulation symbol needing to be sent on the second resource; and in bit combinations corresponding to modulation symbols sent on at least one of the first resource and the second resource, SR bits in at least two bit combinations are different, and ACK/NACK bits in at least two bit combinations are different; characterized in that in the mapping relationship, each bit combination corresponds to one first-type modulation symbol that needs to be sent on the first resource and one second-type modulation symbol that needs to be sent on the second resource, and a value that is of one modulation symbol in the first-type modulation symbol and the second-type modulation symbol and that corresponds to a value of the bit combination is 0, and a value that is of the other modulation symbol and that corresponds to the value of the bit combination is not 0; and correspondingly, the receiving, on one of the first resource and the second resource, a modulation symbol sent by the terminal device comprises: receiving, on the first resource, a first-type modulation symbol whose value is not 0 and that is sent by the terminal device, or receiving, on the second resource, a second-type modulation symbol whose value is not 0 and that is sent by the terminal device.