A method for phase synchronization, wherein the method comprises: receiving, by a receiving device, a spread spectrum signal transmitted by a transmitting device, wherein the spread spectrum signal is obtained by the transmitting device by performing spread spectrum modulation on a signal with a constant amplitude value by using a specific code word; despreading, by the receiving device, the received spread spectrum signal by using the specific code word, to obtain a first despread signal, wherein an amplitude value of the first despread signal is a first amplitude value; adjusting, by the receiving device, a phase value of the specific code word, and despreading the received spread spectrum signal by using the phase-adjusted specific code word, to obtain a second despread signal, wherein an amplitude value of the second despread signal is a second amplitude value; determining, by the receiving device, a first phase difference according to a difference between the first amplitude value and the second amplitude value, wherein the first phase difference is a difference between a phase value of the phase-adjusted specific code word and a phase value of the received spread spectrum signal; and performing, by the receiving device, synchronization processing between the phase value of the phase-adjusted specific code word and the phase value of the received spread spectrum signal by using the first phase difference; characterised in that the performing, by the receiving device, synchronization processing between the phase value of the phase-adjusted specific code word and the phase value of the received spread spectrum signal by using the first phase difference comprises: transmitting, by the receiving device, the first phase difference to the transmitting device, and instructing the transmitting device to add the first phase difference to the phase value of the transmitted spread spectrum signal. receiving, by a receiving device, a spread spectrum signal transmitted by a transmitting device, wherein the spread spectrum signal is obtained by the transmitting device by performing spread spectrum modulation on a signal with a constant amplitude value by using a specific code word; despreading, by the receiving device, the received spread spectrum signal by using the specific code word, to obtain a first despread signal, wherein an amplitude value of the first despread signal is a first amplitude value; adjusting, by the receiving device, a phase value of the specific code word, and despreading the received spread spectrum signal by using the phase-adjusted specific code word, to obtain a second despread signal, wherein an amplitude value of the second despread signal is a second amplitude value; determining, by the receiving device, a first phase difference according to a difference between the first amplitude value and the second amplitude value, wherein the first phase difference is a difference between a phase value of the phase-adjusted specific code word and a phase value of the received spread spectrum signal; and performing, by the receiving device, synchronization processing between the phase value of the phase-adjusted specific code word and the phase value of the received spread spectrum signal by using the first phase difference; characterised in that the performing, by the receiving device, synchronization processing between the phase value of the phase-adjusted specific code word and the phase value of the received spread spectrum signal by using the first phase difference comprises: transmitting, by the receiving device, the first phase difference to the transmitting device, and instructing the transmitting device to add the first phase difference to the phase value of the transmitted spread spectrum signal.