隨著電子商務之盛行，網路廣告逐漸成為廠商傳遞產品訊息之重要管道，而具備集客力的知名網路廣告平台更是廠商增加新產品知名度之利器，而其收費方式亦由單純計算點擊率逐漸演變為近來新興之成交計價模式，即消費者必須購買方才孳生網路廣告費用。然在兩相權衡競爭影響力和曝光度下，如何最適之網路廣告平台選擇成為廠商至關重要之決策。有鑑於過往相關研究之匱乏，本研究藉由建構並分析一賽局理論模型，探討雙佔市場中面臨競爭廠商應如何選擇網路廣告平台，以及網路廣告平台策略與價格競爭和消費者福利間之互動關係，主要獲致之結果包括：(1)在競爭市場結構下，為達減緩價格競爭之目的，均衡時廠商可能選擇低廣告效能且高廣告成本之弱勢網路廣告平台。(2)廣告效能臻於完美的網路廣告平台仍可能為面臨價格競爭之廠商所捐棄。因此在競爭市場結構下，網路廣告平台提升廣告效能，反而可能會流失顧客。(3)品牌間差異程度會抑制兩廠商採用網路共同廣告平台之誘因。(4)網路廣告支出與產品定價間的關係未具單調性，故網路廣告支出與消費者福利間之關係亦未具單調性。

With the growth of the e-commerce, the online advertising becomes one of the most important media to spread product information and the cost-per-action mechanism of online advertising platforms starts to replace the cost-per-click system. Nowadays, the optimal online advertising platform selection is an important issue by considering not only the popularity rate but also the competitive concern. Owing to the rare related studies, we build a model based on the game theory to explore how the duopolistic firms select their online advertising platform and the interaction between the advertising decision and the pricing competition. The main results include that (i) the duopolistic firms under the pricing competition may invest on the online advertising platform with lower click-through-rate and high unit cost. (ii) To improve the click-through-rate may reduce an online advertising platform’s attractiveness in the duopoly case. (iii) The more the brand differentiation, the less likely do the duopolistic firms adopt the common online advertising platform. (iv) the relationship between the advertising expenditure and the retailing price may be non-monotonic, and then the interaction between the advertising investment and the consumer welfare can be also positive or negative.