An in-phase/quadrature, I/Q, signal transmission method, comprising: calculating, by a sending end, a first amplitude value and a first phase value of a first I/Q signal; obtaining, by the sending end, an amplitude quantization level of the first amplitude value and a phase quantization level of the first phase value, wherein the amplitude quantization level is used to indicate an amplitude value transmitted per unit of bit width, and the phase quantization level is used to indicate a phase value transmitted per unit of bit width; quantizing, by the sending end, the first amplitude value according to the amplitude quantization level, to obtain a second amplitude value after the quantization, and quantizing the first phase value according to the phase quantization level, to obtain a second phase value after the quantization; and transmitting, by the sending end, the second amplitude value, the second phase value, the amplitude quantization level, and the phase quantization level to a receiving end, so that the receiving end recovers the first I/Q signal according to the second amplitude value, the second phase value, the amplitude quantization level, and the phase quantization level characterized by at least one of: (a) querying, by the sending end, a preset first quantization factor table for an amplitude quantization factor corresponding to the amplitude quantization level, wherein the first quantization factor table stores a correspondence between amplitude quantization levels and amplitude quantization factors, and the amplitude quantization factor is used to indicate a bit width occupied per unit of amplitude value; and using, by the sending end, a product of the first amplitude value and the amplitude quantization factor as the second amplitude value; and, (b) querying, by the sending end, a preset second quantization factor table for a phase quantization factor corresponding to the phase quantization level, wherein the second quantization factor table stores a correspondence between phase quantization levels and phase quantization factors, and the phase quantization factor is used to indicate a bit width occupied per unit of phase value; and using, by the sending end, a product of the first phase value and the phase quantization factor as the second phase value. calculating, by a sending end, a first amplitude value and a first phase value of a first I/Q signal; obtaining, by the sending end, an amplitude quantization level of the first amplitude value and a phase quantization level of the first phase value, wherein the amplitude quantization level is used to indicate an amplitude value transmitted per unit of bit width, and the phase quantization level is used to indicate a phase value transmitted per unit of bit width; quantizing, by the sending end, the first amplitude value according to the amplitude quantization level, to obtain a second amplitude value after the quantization, and quantizing the first phase value according to the phase quantization level, to obtain a second phase value after the quantization; and transmitting, by the sending end, the second amplitude value, the second phase value, the amplitude quantization level, and the phase quantization level to a receiving end, so that the receiving end recovers the first I/Q signal according to the second amplitude value, the second phase value, the amplitude quantization level, and the phase quantization level characterized by at least one of: (a) querying, by the sending end, a preset first quantization factor table for an amplitude quantization factor corresponding to the amplitude quantization level, wherein the first quantization factor table stores a correspondence between amplitude quantization levels and amplitude quantization factors, and the amplitude quantization factor is used to indicate a bit width occupied per unit of amplitude value; and using, by the sending end, a product of the first amplitude value and the amplitude quantization factor as the second amplitude value; and, (b) querying, by the sending end, a preset second quantization factor table for a phase quantization factor corresponding to the phase quantization level, wherein the second quantization factor table stores a correspondence between phase quantization levels and phase quantization factors, and the phase quantization factor is used to indicate a bit width occupied per unit of phase value; and (a) querying, by the sending end, a preset first quantization factor table for an amplitude quantization factor corresponding to the amplitude quantization level, wherein the first quantization factor table stores a correspondence between amplitude quantization levels and amplitude quantization factors, and the amplitude quantization factor is used to indicate a bit width occupied per unit of amplitude value; and using, by the sending end, a product of the first amplitude value and the amplitude quantization factor as the second amplitude value; and, (b) querying, by the sending end, a preset second quantization factor table for a phase quantization factor corresponding to the phase quantization level, wherein the second quantization factor table stores a correspondence between phase quantization levels and phase quantization factors, and the phase quantization factor is used to indicate a bit width occupied per unit of phase value; and using, by the sending end, a product of the first phase value and the phase quantization factor as the second phase value.