The invention discloses an onboard temperature sensor capable of reducing airflow and steam interference. The temperature sensor comprises a tubular shell body, a thermocouple and a flow guide pipe, wherein the tubular shell body is hollow; one end of the tubular shell body is sealed, and the other end of the tubular shell body is opened, so that a flow guide cavity communicated with the outside is formed in the center of the tubular shell body; furthermore, a small hole is formed in the bottom of the tubular shell body; the thermocouple is fixed in the flow guide cavity; and the flow guide pipe is arranged at a side edge of the tubular shell body and is communicated with the flow guide cavity. By adopting the onboard temperature sensor capable of reducing the airflow and steam interference, disclosed by the invention, the temperature outside an aircraft cabin can be accurately measured.