The invention provides a device for detecting leakage of a seal chamber by infrared imaging technology. The device comprises a gas source, a filter, a pressure regulating valve, an electromagnetic valve, a pressure sensor, a temperature sensor, a thermal infrared imager and a control system, wherein the pressure sensor, the temperature sensor and the thermal infrared imager are connected with thecontrol system through lead wires respectively. A method for detecting the leakage of the seal chamber by the device comprises the following steps that a device to be detected reaches a thermodynamical equilibrium state after inflation, namely heat of a material around a vent released to airflow in unit time is equal to that of the material absorbed from atmosphere around the vent, and a leakage point can be determined through the position with reduced temperature detected by the thermal infrared imager; and the leakage amount can be determined through calculation of a computer in the controlsystem. The device and the method have the advantages that the detecting device has simple structure, easy operation and low cost; the detecting method is practical, has small detection error, and can quickly and accurately detect the leakage point and the leakage amount of a chamber to be detected; and the detecting device and the method have strong applicability and wide application prospect.