A three-phase uninterruptible power supply, UPS, control method, comprising: determining that a zero wire of a three-phase uninterruptible power supply is lost; using an alternating current whose frequency is a harmonic frequency of mains as a 0-axis reference current; and generating a 0-axis modulated wave according to a difference between the 0-axis reference current and a 0-axis sampling current, to control a rectifier in the three-phase uninterruptible power supply to convert a received three-phase alternating current to a direct current, wherein at a same moment, the 0-axis sampling current is one third of a sum of an A-phase current, a B-phase current, and a C-phase current in the three-phase alternating current received by the three-phase uninterruptible power supply; wherein, the generating a 0-axis modulated wave according to a difference between the 0-axis reference current and a 0-axis sampling current specifically comprises: performing proportional adjustment on the difference between the 0-axis reference current and the 0-axis sampling current so that when the zero wire of the three-phase uninterruptible power supply is normal, a location of a wave peak of each of an A-phase modulated wave, a B-phase modulated wave, and a C-phase modulated wave is the same as a location of a wave trough of the 0-axis reference current, and a location of a wave trough of the modulated wave is the same as a location of a wave peak of the 0-axis reference current, wherein a frequency of the 0-axis reference current is a 3N th -order harmonic frequency of the mains, and N is a natural number; and performing amplitude limiting on a difference between a 0-axis sampling voltage and a signal that is output after the proportional adjustment, to obtain the 0-axis modulated wave, wherein at a same moment, a voltage of the 0-axis modulated wave is equal to one third of a sum of a voltage of the A-phase modulated wave, a voltage of the B-phase modulated wave, and a voltage of the C-phase modulated wave. determining that a zero wire of a three-phase uninterruptible power supply is lost; using an alternating current whose frequency is a harmonic frequency of mains as a 0-axis reference current; and generating a 0-axis modulated wave according to a difference between the 0-axis reference current and a 0-axis sampling current, to control a rectifier in the three-phase uninterruptible power supply to convert a received three-phase alternating current to a direct current, wherein at a same moment, the 0-axis sampling current is one third of a sum of an A-phase current, a B-phase current, and a C-phase current in the three-phase alternating current received by the three-phase uninterruptible power supply; wherein, the generating a 0-axis modulated wave according to a difference between the 0-axis reference current and a 0-axis sampling current specifically comprises: performing proportional adjustment on the difference between the 0-axis reference current and the 0-axis sampling current so that when the zero wire of the three-phase uninterruptible power supply is normal, a location of a wave peak of each of an A-phase modulated wave, a B-phase modulated wave, and a C-phase modulated wave is the same as a location of a wave trough of the 0-axis reference current, and a location of a wave trough of the modulated wave is the same as a location of a wave peak of the 0-axis reference current, wherein a frequency of the 0-axis reference current is a 3N th -order harmonic frequency of the mains, and N is a natural number; and performing amplitude limiting on a difference between a 0-axis sampling voltage and a signal that is output after the proportional adjustment, to obtain the 0-axis modulated wave, wherein performing proportional adjustment on the difference between the 0-axis reference current and the 0-axis sampling current so that when the zero wire of the three-phase uninterruptible power supply is normal, a location of a wave peak of each of an A-phase modulated wave, a B-phase modulated wave, and a C-phase modulated wave is the same as a location of a wave trough of the 0-axis reference current, and a location of a wave trough of the modulated wave is the same as a location of a wave peak of the 0-axis reference current, wherein a frequency of the 0-axis reference current is a 3N th -order harmonic frequency of the mains, and N is a natural number; and performing amplitude limiting on a difference between a 0-axis sampling voltage and a signal that is output after the proportional adjustment, to obtain the 0-axis modulated wave, wherein at a same moment, a voltage of the 0-axis modulated wave is equal to one third of a sum of a voltage of the A-phase modulated wave, a voltage of the B-phase modulated wave, and a voltage of the C-phase modulated wave.