Conductive　hydrogel-based　flexible　electronics　have　attracted　immense　interest　in　wearable　sensor,　soft　robot　and　human–machine　interface.　However,　the　application　of　hydrogels　in　flexible　electronics　is　limited　by　the　deterioration　of　mechanical　and　electrical　properties　due　to　freezing　at　low　temperature　and　desiccation　after　long-term　use.　Meanwhile,　flexible　electronics　based　on　hydrogel　are　usually　not　breathable,　which　has　a　great　impact　on　wearing　comfort　and　signal　stability　in　long-term　sensing.　In　this　work,　an　adjustable　porous　gelatin/polypyrrole/reduction　graphene　oxide　(Gel/PPy/rGO)　organohydrogel　with　high　breathability　(14　g∙cm−2∙h−1),　conductivity　(5.25　S/m),　mechanical　flexibility,　anti-freezing　and　long-term　stability　is　prepared　via　the　combination　method　of　biological　fermentation　and　salt-out　toughening　crosslinking.　The　sensor　fabricated　from　the　prepared　porous　organohydrogel　exhibits　excellent　sensing　sensitivity,　fast　response　ability,　and　good　endurance,　which　monitors　both　weak　and　intense　human　activities　effectively　like　finger　bending,　elbow　bending,　walking　and　running,　and　tiny　pulse　beating.　A　pressure　sensor　array　prepared　from　the　porous　organohydrogel　detects　pressure　variation　in　2D　sensitively.　Furthermore,　the　porous　organohydrogel　is　utilized　as　flexible　electrodes　for　the　accurate　collection　and　recognition　of　human　physiological　signals　(EMG,　ECG)　and　as　an　interface　between　human　and　machine.　©　2022　Elsevier　Inc.