Instrumented　indentation　technique　has　been　increasingly　utilized　to　measure　the　mechanical　properties　of　soft　polymers　and　biological　tissues.　However,　the　indentation　behaviors　of　these　materials　has　not　been　well　understood,　especially　the　parameter　identification　of　their　hyperelastic　material　properties.　In　this　paper,　we　developed　a　spherical　indentation　data　analysis　method　to　directly　extract　the　isotropic　uniaxial　stress-strain　relationship　of　hyperelastic　soft　materials　from　the　measured　spherical　indentation　load-displacement　curves.　The　proposed　method　mainly　included　new　measure　of　indentation　stress　and　strain,　which　was　built　based　on　the　Hertz　load-displacement　relationship　and　further　revised　by　considering　the　non-Hertzian　effects　of　neo-Hookean　hyperelastic　contact　problems.　Numerical　and　actual　indentation　experiments　showed　the　proposed　definition　of　indentation　strain　can　properly　evaluate　the　amount　of　nonlinear　strain　for　neo-Hookean,　Yeoh　and　Arruda-Boyce　hyperelastic　materials.　Meanwhile,　the　proposed　spherical　indentation　data　analysis　method　was　applicable　only　in　certain　deformation　range　for　Yeoh　and　Arruda-Boyce　hyperelastic　materials,　because　their　nonlinear　material　parameters　might　cause　very　complicated　contact　pressure　distributions.　Building　a　universal　data　processing　technique　for　characterizing　the　hyperelastic　mechanical　properties　of　soft　materials　through　indentation　experiments　still　needed　further　investigations.　(C)　2018　Author(s).