This application provides a method and an apparatus for controlling a grid-tie inverter. The method includes: acquiring an output voltage of the grid-tie inverter and an output current value of the grid-tie inverter at a current moment; calculating N output current values of the grid-tie inverter at a next moment that is in one-to-one correspondence to N switch states of the grid-tie inverter based on the output current value at the current moment, and N is a natural number greater than or equal to 2; acquiring a first reference current based on the output voltage; acquiring a second reference current based on the output current and the first reference current; determining a first switch state; and controlling the grid-tie inverter to perform power transmission in the first switch state at the next moment.