Abstract: The beam pipe is located in the center of the Beijing Spectrometer Ⅲ (BES Ⅲ). It is a vacuum sandwich pipe with the thinnest wall thickness of 0.6 mm. During the operation of the new generation Beijing Electron and Positron Collider (BEPC Ⅱ), the inner surface of the beam pipe is subjected to high radiation heat loads of high order mode radiation (HOM) and synchrotron radiation (SR), which will lead to the generation of the thermal stress. Hence, a beam pipe with cooling structure was designed, and stress fields of the beam pipe were studied by experiment and finite-element simulations. When the beam pipe was installed that one end was fixed completely and the other end was free along the axis, and the thermal load on the inner surface of the beam pipe reached its maximum value of 750 W, the results show that the maximum stress of the beryllium pipe, aluminum enlarged cavity, silver transition tube, copper tube and stainless steel flange are 21.9、6.9、5.0、9.1、24.4 MPa respectively. The safety factor of the beam pipe is 11.0. At present, the BES Ⅲ beam pipe is operating safely, thereby ensuring that BEPC Ⅱ operates normally and that BES Ⅲ detects particles accurately.