Abstract: The deflection span ratio of long-span is the same as the storey displacement angle of multi-storey and high-rise buildings, which has always been an important index of design control. The structural design of the protective building project of Zhoukoudian Site (Peking Man Cave) is comprehensively and carefully introduced from the perspective of structural stability in Overall Stability Capacity Analysis of Long-Span Single-Layer Special-Shaped Shell. Based on the limit value of deflection span ratio and seismic stability of reticulated shells, it further discussed the project in order to attract the attention and participation of colleagues in the industry.