This paper collects 44 cases of steel bridges damaged by instability at home and abroad, and analyzes the statistical characteristics from the causes of damage, the phase of failure, the bridge typ, the span and the use of bridge. The results show that the large slenderness ratio is the primary cause of instability of steel bridge which accounts for about 79.5%. Meanwhile, the instability of the construction process accounts for about 70.5%, which is much higher than the service phase. In this paper, the typical cases of each type of instability are selected for finite element modelling analysis or discussion on mechanical level to comb out the failure mechanism of various steel bridge instability failure problems. Based on this, several engineering proposals are proposed to prevent the instability of steel bridges which have reference value for actual engineering.

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