Firstly, the paper analyzes the relationship between the urban agglomerations and the enterprise competitive advantage based on knowledge network, then constructs enterprise external competitive advantage function in urban agglomerations, analyzes the constraint conditions of enterprise external competitive advantage maximization and discusses the variable mechanism of knowledge network readiness function in urban agglomerations. Finally, taking enterprise external competitive advantage of Yangtze triangle urban agglomerations as an example, this article analyzes its present situation and readiness of knowledge network, then analyzes its enterprise external competitive advantage, and puts forward the improving path of enterprises external competitive advantage by optimizing knowledge network.