Abstract: The diameter calculation is the primary task in the design of the TEG dehydration packed tower. In order to select the accurate and applicable method for diameter calculation, several methods were illustrated in detail. Two actual projects were selected as calculation cases, and the Bain-Haugen correlation method, the general pressure drop correlation graph method (GPDC), the tower load coefficient method, the Aspen HYSYS software were selected to calculate the diameter of TEG dehydrating packed tower, and the deviation analysis of the calculation results and the applicability analysis of the calculation method were carried out. The result showed that the calculation results of the tower load coefficient method, the GPDC method and the Aspen HYSYS software were similar and the rounded tower diameter was consistent, and the deviation of the Bain-Haugen correlation method was large and conservative, which were 11.11% and 8.73% respectively. The calculated results accuracy of the GPDC method was difficult to be guaranteed by the influence of data points in the GPDC graph. The tower load coefficient method and the Aspen HYSYS software were recommended to calculate the diameter of TEG dehydration packed tower.