City is composed of many situations. How to constructe lively situations in the daily life is the source of urban vitality. The situationist is regarded as a very influential social thoughts in the Mid and late 20th Century in Europe. Facing the poverty of modernism,the situationists' ultimate goal was to reconstruct the entire city and they put forward the idea of "unitary urbanism","constructing situation","complex space". This paper probes into the thought of Situationism and puts fo...