Abstract: In order to optimize the TEG dehydration process in an offshore gas field, determine reasonable parameters and achieve the optimal treatment effect, the HYSYS model was established to make a simulation under certain working conditions that the natural gas treatment capacity was 2×10⁶ m³/d, the operation pressure (gauge pressure) of absorber was 10 600 kPa, and the lean TEG circulation was 1.17 m³/h. The relationship between independent variables and dependent variables was obtained by simulating and optimizing the inlet temperature of natural gas and lean TEG, lean TEG mass fraction, reboiler temperature, and stripping gas flow. On this basis, the optimum operation parameters were obtained to guide the process. It was verified that under the conditions of optimum parameters that the inlet temperature of natural gas was 33 ℃, the inlet temperature of lean TEG was 40 ℃ and the lean TEG mass fraction was 99.30%, the natural gas dehydration system operated normally, and the dew point of the dry natural gas reached the standard of natural gas transportation in platform. It showed that the HYSYS software could simulate and optimize the field process parameters according to the actual working conditions, and the results were relatively accurate. It could be popularized and applied in other offshore gas field.