The invention discloses a superhigh-temperature and high-pressure check valve. The superhigh-temperature and high-pressure check valve comprises a valve body. The upper end of the valve body is provided with a fixed block. A valve rod penetrates through the fixed block. The upper end of the valve rod is provided with a turning wheel. The lower end of the valve rod is provided with a mounting block. A device cavity is formed in the middle of the mounting block. A guide rod is arranged in the device cavity. The guide rod is sleeved with two movable plates. The sidewalls of the two movable platesare both provided with insertion rods. The two insertion rods penetrate through the inner wall of the device cavity. Two round cavities are formed in the sidewall of the mounting block. The two roundcavities are located on the two sides of the device cavity. The inner walls of the two round cavities are both provided with sliding cavities which communicate with the device cavity. The inner wallsof the round cavities are fixedly connected with the fixed block. The superhigh-temperature and high-pressure check valve is reasonable in structure design and easy to operate. The service life of the superhigh-temperature and high-pressure check valve is greatly prolonged by adopting a replaceable valve clack. Meanwhile, the enterprise cost is lowered.