Abstract: As an excellent raw material for floor and high-quarlity furniture,Eucalyptus camaldulensis lumber is hard to be dried and most drying defects are collapsed and split.In this paper,steaming is used to recover the collapsed Eucalyptus lumber and collapse coefficient is proposed as an index of the collapse severity.The results show:The cross-sectional area and height collapse coefficient of 20 mm thick board decrease from 25.1% to 5.87% and from (25.5%) to 6.36%,respectively.The cross-sectional area and height collapse coefficient of (25 mm) thick board decrease from 22.85% to 5.34% and from 23.2% to 5.28%,respectively.Most collapse recovery happens in the early stage of steaming and correlates with MC change strongly.Steaming is a promising method to recover collapsed lumber and should be studied further.Some advices are also given for the further study.