The technical structure of a composite function block with self thermal insulation is introduced. Block — thermal insulation layer-protective layer trinity is achieved through setting tie bars within the block. The block not only collects multiple functions to one body, such as load-carrying/maintenance, thermal insulation, drainage and exhaust, anti-shedding and anti-crack for surface layer etc. But also it collects both safety and durability to one body. The kind of block has many characteristics such as maintenance-free, strong compound function and so on. The block can greatly avoid quality defects of the wall block building non-structural cracks though structure measures, and has been confirmed by the pilot building.