The invention relates to the technical field of fire alarm, in particular to a household combustible gas detector with an index curve correction function, which can improve the detection precision andensure the communication effect, a CPU module comprises a single chip microcomputer U1, the single chip microcomputer U1 is in electric control connection with a calibration signal processing circuitand a bus communication circuit, the bus communication circuit comprises an optocoupler U4, a first pin of the optocoupler U4 is connected with a 3.3 V power supply, a second pin of the optocoupler U4 is connected with a 42 pin of the single-chip microcomputer U1 through a resistor R37, a fourth pin of the optocoupler U4 is connected with a DC + direct-current power supply, and a third pin of theoptocoupler U4 is connected with one end of a resistor R30. The other end of the resistor R30 is connected with a base electrode of a triode Q3 and one end of a resistor R31, and a third pin of the triode Q3 is connected with one end of a resistor R29. The other end of the resistor R29 is connected with one end of a resistor R33, an anode of a diode D9 and a pin 3 of a common-cathode diode D7; apin 2 of the common-cathode diode D7 is connected with a pin 1 of a common-anode diode D8, one end of a capacitor C28, one end of a common-cathode voltage-regulator tube D6 and one end of a resistor R27; and a pin 1 of the common cathode diode D7 is connected with a pin 2 of the common anode diode D8, one end of the capacitor C29, one end of the resistor R28 and the other end of the common cathodevoltage stabilizing tube D6.