Abstract：In this paper, a new self thermal insulation mural material is proposed. Its major components include nanometer SiO2, portland cement and fly ash. It is made by mixing shrinkage-reducing agent, filling waste polystyrene in the hole, and natural curing. It is called the nano-silica doped flyash sandwich block. Based on the design requirements and standards of ordinary fly ash concrete hollow block, the corresponding size of the block, the size and distribution of the holes for this material are determined. The influences of major-factors such as fly ash, nanometer material, portland cement and water on the strength of the block are studied. The bending strength is the most important. Four factors and three levels for the orthogonal experiment are selected to optimize the matching ratio of the block. The result is 40% of fly ash, 14% of the portland cement, 0.5% of nanometer SiO2 and 22% of the water ash ratio. Such block features high bending strength and low cost. The bending strength and the compressive strength reach the same factor level combination as being reached in previous studies, but with higher ratio of bending strength to compressive strength. The block made by such matching ratio has a higher compressive strength and a higher flexural strength. The masonry made by such block can better withstand complex stresses.