Abstract: Public City Crisis is a direct threaten to public safety.And public crisis is often amplified in scope and degree due to its effect of amplifying and chaining.

• 摘 要: 城市公共危机是城市公共安全的直接威胁，由于城市公共危机具有放大效应和连锁效应，往往使公共危机的危害范围和危害程度加大。