Fire detection sensor

The invention is suitable for the technical field of security and protection, and provides a fire detection sensor, the fire detection sensor is provided with a dust containing cavity above a flue bone position, when dust and small-particle sundries enter the inner surface of the dust containing cavity, a transmitting tube emits light which cannot irradiate the dust and the small-particle sundries, the original signal value of the sensor is not changed, and the smoke alarm does not give an alarm, so that false alarm is avoided. Besides, the two transmitting tubes and the two receiving tubes are obliquely installed on the lower cover and face the center of the smoke inlet cavity, light emitted by the transmitting tubes irradiates the interior of the containing cavity, diffuse reflection or scattering is generated, the light cannot directly irradiate the lower cover, it is avoided that when dust appears on the lower cover, the signal value of the sensor is affected, and false alarms are further reduced; moreove