Joint　interfaces　static　stiffness　is　closely　related　to　the　connection　mode,　bolted　member　stiffness　and　joint　part　stiffness.　It　is　very　difficult　to　measure　and　calculate　the　joint　interfaces　static　stiffness　directly.　Taking　bolted　joint　interfaces　as　research　objects,　a　method　of　extracting　the　normal　static　stiffness　of　bolted　joint　interfaces　was　proposed.　By　combining　the　spplication　of　normal　static　stretching　experiment　and　data　processing,　the　joint　part　stiffness　was　obtained.　Then　an　optimization　calculation　on　bolted　member　stiffness　was　carried　out　and　a　corresponding　refined　analytic　formula　was　provided.　Based　on　the　exploitation　of　relationships　among　the　joint　interfaces　static　stiffness,　bolted　member　stiffness　and　joint　part　stiffness　the　normal　static　stiffness　of　bolted　joint　interfaces　was　seperated　from　the　whole　bolted　joint　part　stiffness.　In　accordance　with　the　above　analysis　results,　the　nonlinear　characteristic　curve　of　normal　static　stiffness　of　bolted　joint　interfaces　corresponding　to　effective　contact　pressure　was　extracted.　The　method　proposed　provides　a　new　way　to　the　in-depth　study　about　joint　interfaces　static　stiffness.