開放原始碼軟體在近年來為資訊產業的熱門話題,本文建立一經濟模型,來描繪開放原始碼廠商與封閉原始碼廠商之間的競爭。我們發現,給定生產封閉原始碼軟體的技術水準,網路效果強度相對於消費者對廠商產品的偏好程度較大時,開放原始碼軟體的使用者修改軟體的行為,必然會使開放原始碼軟體的品質上升;但當網路效果強度相對於消費者對廠商產品的偏好程度較小時,開放原始碼軟體的使用者修改軟體,則未必能使開放原始碼軟體的品質上升。 The paper investigates the price and quality competition between an open source and a closed source software. It is often believed that one of the advantages of open sources is that it enables the users to access the source, and thus voluntarily modify and improve the quality of the software. The results of our model show that, given the quality of closed source software, if the degree of network externalities is large relative to the intensity of the users` preferences, then this is indeed the case. If, however, the degree is small relative to preferences, then the quality does not necessarily improve.