This paper introduces the structure and completion method of the new Su20 well. The inner diameter of the upper casing is 146mm,and the inner diameter of the lower casing is 180mm. We analyze the monitoring efficiency,and compare the response ability of different well structures from the way of diurnal tide difference,peak and valley time,M2 wave tide factor and so on. At the same time,some suggestions for future well construction of seismic system are given,that is,to construct wells according to new structures and techniques,so as to improve the response ability of seismic observation wells to crustal stress and strain.