The invention relates to a circular ring 
ion trap and a circular ring 
ion trap array used for an 
ion storage device with ultra high capacity and a 
mass analyzer which is used for carrying out the separation and the detection according to the characteristics of an ion, such as the 
mass-to-charge ratio of the ion, and the like. The circular ring 
ion trap comprises an ion lead-in hole and an ion lead-out hole. Two parallel annular electrodes with flat hollow circular ring structures, and two cylindrical circular rings with different outside diameters and perpendicular to the flat annular electrodes form an inner and an outer boundary electrodes. The two flat annular electrodes are arranged in parallel and vertically, and share the same axis center with the two boundary electrodes; the boundary 
electrode with a small 
diameter is positioned on the inner side of the flat hollow annular electrodes; the boundary 
electrode with a large 
diameter is positioned on the outer side of the flat hollow annular electrodes; a gap or an insulating material is arranged in the boundary electrodes and the flat annular electrodes, so as to ensure the electric insulation among the electrodes; a high-frequency 
voltage signal is applied to the upper and the lower flat annular electrodes; the boundary electrodes are grounded or a 
DC voltage is applied to the boundary electrodes to form an ion 
storage area. Under the externally applied 
electric field, the ion is captured, stored, cooled or optionally discharged outside a trap.