The identity of a city matters in a global age. This article explores the discursive construction of the global city's identity in relation to semiotic landscape, using the construction of Shanghai as a global city as a case study. In this increasingly globalising world, Shanghai authorities have recently demonstrated the desire to establish itself as a global city. Under the assumption of city agency in the semiotic practice of public signage, the signs photographed on site at Pudong International Airport of Shanghai were analysed from a critical perspective of multimodal discourse analysis, focusing on identity building for unique selling propositions. Questions addressed include what the identity of the global city looks like in Shanghai and how Shanghai is semioscaped as a global city and thereby its ethos implicitly represented. The findings suggest both global convergences and local particularities in the semioscaping of Shanghai as a global city. It argues that this way of identity building is attributable to the negotiation and contestation of power subject to the social norms, ideologies of a specific city.