Air tightness detection device and method, and locomotive air tightness detection system and method

The invention discloses an air tightness detection device and method, and a locomotive air tightness detection system and method. The air tightness detection device comprises: a detection assembly used for collecting an ultrasonic signal of a to-be-detected position and converting the ultrasonic signal into an electric signal; a robot used for conveying the detection assembly to a to-be-detected position; output equipment used for outputting a detection result; and a control terminal used for controlling the robot to run according to a preset track after receiving the operation instruction, converting the electric signal into a detection result after receiving the electric signal, and controlling the output equipment to output. According to the air tightness detection device, the ultrasonic signal generated during gas leakage is converted into the detection result that an operator can directly judge the air tightness, the operator does not need to climb to the top manually, and then brush soapy water and obse