本文設立一個雙佔模型來討論廠商的均衡遊說行為、有遊說活動下之最適關稅及開放廠商進行遊說活動對利潤及社會的影響。本文得到的結論為當本國的生產者剩餘在政府的目標函數之權重愈大時，本國廠商會有愈強的誘因進行遊說；此外，當外國廠商的遊說支出移轉至政府的目標函數比例愈大時，外國廠商跨國遊說的誘因會增強。值得強調的是，若外國廠商從事跨國遊說，遊說支出有愈高比例移轉到政府的目標函數時，不但外國廠商的利潤會提高，執政者追求的目標也會提昇。此一結論與一般人認為開放跨國遊說不利於政府所追求的目標之認知不盡相同。

This paper sets up a duopolistic model to discuss the lobbying incentives, the optimal tariff under lobbying activities, and the impact of opening up international lobbying on firms' profits and on society. The findings show that the domestic firm has a stronger incentive to conduct lobbying when the government has a higher affinity toward producer surplus in its objective function. In addition, the incentives for the foreign firm to conduct cross-border lobbying are enhanced when the proportion of foreign firm' lobbying expenditure that shifts to the government's objective function is larger. Given the foreign firm's cross-border lobbying, the results emphasize that not only does the foreign firm's profit increase, but also the goal pursued by the domestic government rises when the proportion of foreign lobbying expenditure that shifts to the domestic government is higher. This conclusion is in stark difference to the common conception that opening up international lobbying is not conducive to the government's goal.