In the high-rise building, the conversion layer is often set when the structure of upper and lower floors are different. This conversion layer plays the role of transitional connection. But the force is complex, the conversion layer is the weak layer of the structure and it is the difficulties of the structure design and building construction. However, conversion layer has large section size, bulky, complicated structure the temperature stress to generated cracks in long-span beam type conversion layers. In this paper, directed towards the long-span beam type conversion layer characteristics, combined with tempertural stress in mass concrete causes, proposed control points of long-span beam type conversion layer . It has practical directive significance for long-span beam type conversion layer.