[en] The vacuum system of TRISTAN in National Laboratory for High Energy Physics experienced various problems due to RF wave and wall current arising by beam running during its six years operation. To these problems, at present the countermeasures have been empirically taken, such as the holes in the exhaust system are made small, RF shield is attached to the bellows, RF contact is provided for the flange part and so on, thus obstruction does not occur in the beam operation. In order to carry out the design taking these effect in consideration, it was decided to examine the RF power and to obtain the quantitative data of beam impedance and others. The data acquisition is carried out by the calculation with a large computer and the evaluation test using a test chamber piece. In this paper, first the problems actually occurred in the incidence storage ring and the electron-positron collision ring of TRISTAN are explained, and next, as the example of calculation with a large computer, the results of the calculation of the impedance of bellows in both storage ring and collision ring are shown. The trend of impedance change due to the shape change of bellows and gaskets was able to be grasped. (K.I.)