Abstract: Because of the limit of field and the need of buildings function, the high buildings in the earthquake area can not meet the criterion that “the plane and frontispiece of seismic buildings should be regular symmetrically”, so it is unavoidable to set seismic joint. How to set seismic joint suitably and how to adopt simple or practical methods for determining seismi
c joint width were deeply studied. The paper discusses the current seismic criterion about the least width of seismic joint and advises to change the conventional methods of setting the least width of seismic joint; moreover, designers can adopt the apical displacement method to decide the least width of seismic joint.