The concealed stainless steel fastener is used to connect the metal roof panel and the supporting layer, and the metal roof surface after vertical bite has no influence. Stainless copper fasteners (including fixed fasteners and sliding fasteners) are synchronized with the longitudinal metal roof panel, which can solve the plate stress caused by thermal expansion and contraction. In the production of lengthwise and super long size roofs, the roof panel uses a step structure piecewise overlap to completely change the existence of large area metal roofs. The expansion of metal roofs caused by temperature difference will not cause cracking, deformation and abrasion of roofs due to plate stress. At the same time, the complete appendix of the system can meet all kinds of architectural form requirements.