The invention provides a superhigh temperature flowmeter with a protecting function. The flowmeter comprises a measuring tube and an integrating meter connected with the measuring tube, wherein the measuring tube is connected with the integrating meter through a connecting base, an air chamber base and a transition connecting pipe which are connected from bottom to top in sequence, and a sensor is arranged in the air chamber base. The flowmeter further comprises a protecting structure connected with the air chamber base, wherein the protecting structure comprises a round steel pipe, an external thread matched with an internal thread in the air chamber base is machined at one end of the round steel pipe, and a boss ring is formed at the other end of the round steel pipe in an integrated mode; the end, away from the round steel pipe, of the boss ring is connected with a corrugated pipe, a connecting ring is arranged at the end, connected with the boss ring, of the corrugated pipe, and a welding port welded to a target rod of the sensor is formed in the other end of the corrugated pipe; cool fin sets are arranged on the outer wall of the connecting base and the outer wall of the transition connecting pipe respectively. By the adoption of the flowmeter, temperature and impurity insulation is achieved, and the sensitivity and service life of the sensor are not affected. By arranging the cooling fin sets, metering precision is higher, and stability is higher.