The invention discloses a smart city system based on big data, which is used for solving the problem that the existing smart city system is lack of intelligent adjustment and intelligent distribution,can realize city planning, management and service by analyzing city information, and has more comprehensive functions. Autonomous city planning is generated during city planning, planning evaluationis carried out according to city implementation conditions, and the obtained planning scheme is more suitable for city development requirements; position information, demand information and identity information acquired by an intelligent acquisition terminal are stored in a big data platform to form pseudo-materialization prediction data corresponding to the identity information, pseudo-materialization prediction is performed on urban residents through the pseudo-materialization prediction data, and intelligent allocation is performed on user demands through an intelligent allocation terminal;the life convenience and flexible demand arrangement of urban residents are improved, so that the city is more intelligent and more personified; and the emergencies and emergencies are adjusted through the intelligent adjusting terminal.