Disclosed in the utility model is an annular supporting structure of an inner tube thin-wall portion of a micro metal dewar. The annular supporting structure comprises an upper supporting ring, a lower supporting ring and reinforced ribs connecting the upper supporting ring and the lower supporting ring. The upper supporting ring and the lower supporting ring are parallel to each other and are coaxial. There are three or more reinforced ribs connecting the upper supporting ring and the lower supporting ring and the reinforced ribs are uniformly distributed in a 360-degree range; cross sectional areas of the reinforced ribs are equal to or less than 0.16 mm<2>; included angles between the reinforced ribs and the upper supporting ring and the lower supporting ring is from 20 degrees to 70 degrees; and the reinforced ribs are in rigid connection with the upper supporting ring and the lower supporting ring. The annular supporting structure employs a titanium alloy material with high thermal resistivity. According to the utility model, anti-vibration and shock-resistant capabilities of the micro metal dewar can be effectively enhanced; and vibration displacement of an infrared focal plane detector chip installed at the bottom of the inner tube of the dewar is controlled to be within 1.5 microns and is less than 1/10 of a pixel size of the chip of the detector, thereby meeting a strict requirement of high precision imaging on a detector assembly in a complicated dynamic environment.