The invention discloses a temperature detection and signal transmission device under vacuum environment. The temperature includes a measurement emitting part inside a vacuum container and a receiving displaying part outside the vacuum container. In the measurement emitting part inside the vacuum container, a thermocouple, a signal collecting and amplifying circuit, a modulus A/D switching circuit are connected with a first singlechip in sequence; a temperature-compensation circuit is connected with the first singlechip, an ultrasonic radiating circuit and an ultrasonic radiating head in sequence; in the receiving displaying part outside the vacuum container, an ultrasonic receiving head is connected with an ultrasonic receiving circuit, a singlechip, and a LED electronic display screen in sequence. The temperature detection and signal transmission device under vacuum environment has the beneficial effect of being capable of reaching the goal of accurately measuring, transmitting and displaying the temperature of the point to be measured inside the vacuum container by transmitting and receiving a temperature signal through ultrasonic under the premise of not destroying the sealing performance and insulating performance of the vacuum container.