Regarding the problem of excessive deformation of double steel sheet-pile in soft soil stratum，we take a foundation pit of a shipyard as an example，study the deformation characteristics of double steel sheet-pile in soft soil stratum by means of field test data analysis，theoretical calculation and numerical simulation，and analyze the causes of excessive deformation. By means of the identification of limit state and the inversion of critical state parameters，we put forward the emergency treatment method of backfill back pressure according to the field data and reinforcement measures of double-row cast-in-place piles with large row spacing. The results show that the proposed emergency treatment method and reinforcement measures achieve good results.Double steel sheet-pile cofferdam is often deformed greatly in soft soil foundation pit，and it will be deformed rapidly when it enters critical state. Effective reinforcement measures should be taken to avoid overbreak.