The evolution of media has made the capability of human information communication constantly extend and improve in time and space, affected people's thoughts and behaviors, and further affected social development and urban civilization. The question of how to safeguard social fairness, justice and the legitimate rights and interests of the public has become a core issue in the process of urban planning. Social sensing collects the information of urban physical environment or social environment from human beings or their equipment, which has become an important technical guarantee of planning social process. This chapter starts from the analysis of the interaction between media, people and cities, then explores the method of improving the perception of urban planning from massive social media texts by utilizing social sensing based on semantic computing. It aims to strengthen the connection between planning and society through social media and improve the scientific nature and practicability of planning results.