Abstract: Accrding to the basic theory of systems engineering,the oil/gas reservoir is regarded as an open,discrete.non steady and controlable system,and which is studied by the system analysis method.After describing the reservoir damage system and explaining the object and characterics of system,this paper focuses,the discussion focuses on the analysis and evaluation of structure and environment of system Lastly,the reasons to cause The causes of the reservoir damage and the relevant protection measures are presented in this paper.