The invention discloses an SPB storage tank accumulation type insulation system. The insulation system is mainly composed of prefabricated insulation plates and buffer structure between the adjacent insulation plates. The prefabricated insulation plates are fixed to the outer wall of a storage tank through the plate centers via double-screw bolt structures. The buffer structure is composed of several different heat insulation materials, and relative motion under the condition of heat expansion and cold shrinkage is absorbed. According to the system, under the condition of guaranteeing that thelow-temperature heat insulation performance is not influenced, the connecting manner at the Joint is optimized and upgraded, the locating precision of a connector is improved, and the SPB storage tank accumulation type insulation system aims at reducing the construction difficulty and quality control difficulty and improving the construction efficiency and quality.