By　using　flexible　material,　there　are　lots　of　researches　on　soft　robot　arm　for　taking　its　advantages.　Compare　with　conventional　rigid　manipulator,　soft　robot　arm　can　provide　dexterity,　safety　and　light　weight.　Besides　upon　unique　characteristics,　researchers　also　focused　on　solving　its　disadvantages　like　weak　stiffness.　This　paper　introduces　a　novel　soft　pneumatic　robot　arm　with　multi-section　serially　connection　and　variable　stiffness　by　coupling　structure.　One-section　arm　consists　of　two　connecting　plates　on　the　upper　and　bottom,　three　motion　air　chambers　between　in　the　plates　and　variable　stiffness　air　chamber　in　the　middle.　There　are　three　fields:　static　mechanical　modeling,　kinematic　tests　and　variable　stiffness　analysis　in　this　paper　to　demonstrate　the　design　can　be　a　solution　to　overcome　current　limitation　of　soft　robot　arms.　Also,　this　paper　evaluates　the　kinematic　and　mechanical　characteristics　through　experiments　and　finally　the　validity　of　this　multi-section　and　variable　stiffness　design　in　couple　approach　is　proved.　©　2019,　Springer　Nature　Switzerland　AG.