The matching of crack tip constraints is a difficult problem in the current structure integrity assessment method.Due to the restriction of current constraint parameters,the matching of crack tip constraints between different laboratory specimens,between laboratory specimens and actual structures have not been established. In this paper,based on the unified constraint parameter A,p,the constraints of different SENB,CT,SENT and CCT specimens were studied,the J/J,ref,-（A,p,）,1/2, correlation lines and the matching of crack tip constraints between different laboratory specimens were established. This study will provide scientific support for building an accurate structure integrity assessment method which considers constraint.