The invention discloses a power supply control system used for an intelligent gas meter. The power supply control system comprises a main power supply, a standby power supply, an MOS transistor, a first diode, a second diode, an LDO voltage stabilizer, a capacitor, a first resistor and a single-chip microcomputer. Control programs are preset in the single-chip microcomputer. Switching from the main power supply to the standby power supply is realized by the control programs set in the single-chip microcomputer so that hardware cost is saved, and on/off of a working module power supply and disconnection of the standby power supply are also realized. On/off time of the power supply is preset in the control programs, and the fixed point on/off and cycle of the power supply are controlled so that flexible control of the power supply is realized and energy consumption is saved.