The invention discloses a control method of low-power consumption operation of a four-phase direct-current voltage-reduction circuit and a logic control unit of the control method. The control method is characterized in that along with reduction of load current, the system is enabled to continuously work in a continuous conducted working state, an interrupted conducted working state, a DCM_DEEP state and a PSM state; the continuous conducted working state refers to a working state where the inductance current is larger than zero all the time; the interrupted conducted working state refers to a working state where the inductance current is zero in a certain time; in the DCM_DEEP state, the third phase and the fourth phase are turned off and only the first phase and the second phase are left to alternatively work; and in the PSM state, only the first phase is left to work, unnecessary modules like a current balancing module are turned off, an output comparator and a band gap reference module are left to work in the system, and the bias current of the output comparator is adjusted to be the smallest so that the steady-state power consumption of the comparator is smallest. In this way, steady-state power consumption of the system can be greatly reduced and standby time of the system is increased.