A signal transmission method, comprising: obtaining, by a terminal device, to-be-transmitted data and uplink control information; encoding, by the terminal device, the uplink control information based on a correspondence between modulation order and encoded uplink control information in Table 6 when the uplink control information is 1 bit, or based on a correspondence between modulation order and encoded uplink control information in Table 7 when the uplink control information is 2 bits, wherein the uplink control information comprises a hybrid automatic repeat request, HARQ-ACK; modulating, by the terminal device, the data and the uplink control information based on a modulation scheme for the data and a modulation scheme for the uplink control information; and transmitting the modulated data and the uplink control information on a physical uplink shared channel: Table 6 Encoding of 1-bit HARQ-ACK Q m Encoded HARQ-ACK 1 o 0 ACK 2 o 0 ACK y 4 o 0 ACK y x x 6 o 0 ACK y x x x x Table 7 Encoding of 2-bit HARQ-ACK Q m Encoded HARQ-ACK 1 o 0 ACK o 1 ACK o 2 ACK 2 o 0 ACK o 1 ACK o 2 ACK o 0 ACK o 1 ACK o 2 ACK 4 o 0 ACK o 1 ACK x x o 2 ACK o 0 ACK x x o 1 ACK o 2 ACK x x 6 o 0 ACK o 1 ACK x x x x o 2 ACK o 0 ACK x x x x o 1 ACK o 2 ACK x x x x wherein modulation orders 1, 2, 4, and 6 respectively correspond to modulation schemes π /2 binary phase shift keying, π /2-BPSK, quadrature phase shift keying, QPSK, 16 quadrature amplitude modulation, 16QAM, and 64QAM; o 0 ACK indicates a bit of the 1-bit uplink control information, o 0 ACK and o 1 ACK indicate bits of the 2-bit uplink control information, o 2 ACK = o 0 ACK + o 1 ACK mod 2, and y and x are placeholders, and where at least one HARQ-ACK comprised in the uplink control information is encoded using modulation order 1 according to table 6 or table 7. obtaining, by a terminal device, to-be-transmitted data and uplink control information; encoding, by the terminal device, the uplink control information based on a correspondence between modulation order and encoded uplink control information in Table 6 when the uplink control information is 1 bit, or based on a correspondence between modulation order and encoded uplink control information in Table 7 when the uplink control information is 2 bits, wherein the uplink control information comprises a hybrid automatic repeat request, HARQ-ACK; modulating, by the terminal device, the data and the uplink control information based on a modulation scheme for the data and a modulation scheme for the uplink control information; and transmitting the modulated data and the uplink control information on a physical uplink shared channel: Table 6 Encoding of 1-bit HARQ-ACK Q m Encoded HARQ-ACK 1 o 0 ACK 2 o 0 ACK y 4 o 0 ACK y x x 6 o 0 ACK y x x x x Table 7 Encoding of 2-bit HARQ-ACK Q m Encoded HARQ-ACK 1 o 0 ACK o 1 ACK o 2 ACK 2 o 0 ACK o 1 ACK o 2 ACK o 0 ACK o 1 ACK o 2 ACK 4 o 0 ACK o 1 ACK x x o 2 ACK o 0 ACK x x o 1 ACK o 2 ACK x x 6 o 0 ACK o 1 ACK x x x x o 2 ACK o 0 ACK x x x x o 1 ACK o 2 ACK x x x x wherein modulation orders 1, 2, 4, and 6 respectively correspond to modulation schemes π /2 binary phase shift keying, π /2-BPSK, quadrature phase shift keying, QPSK, 16 quadrature amplitude modulation, 16QAM, and 64QAM; o 0 ACK indicates a bit of the 1-bit uplink control information, o 0 ACK and o 1 ACK indicate bits of the 2-bit uplink control information, o 2 ACK = o 0 ACK + o 1 ACK mod 2, and y and x are placeholders, and where at least one HARQ-ACK comprised in the uplink control information is encoded using modulation order 1 according to table 6 or table 7.