The　cost-effective　construction　of　self-designed　conductive　graphene　patterns　is　crucial　to　the　fabrication　of　graphene-based　electrochemical　devices.　Here,　a　label-free　carcinoembryonic　antigen　(CEA)　electrochemical　immunosensor　is　developed　based　on　the　surface　engineering　of　a　laser-induced　graphene　(LIG)/Au　electrode.　The　LIG　electrode　was　produced　with　a　smart　and　inexpensive　450　nm　semiconductor　laser　through　three　electrode　patterns　under　ambient　conditions.　Then　the　LIG/Au　electrode　was　organized　by　conformal　anchoring　of　Au　nanoparticles　(NPs)　on　the　LIG　work　area　using　chloroauric　acid　as　the　precursor.　Good　electrochemical　activity　with　improved　conductivity　of　the　LIG/Au　electrode　was　obtained　under　optimized　conditions　of　laser　intensity,　carving　depth,　and　chlorogenic　acid　dosage,　to　name　a　few.　The　LIG/Au　electrode　was　carbonylated　based　on　Au-S∼COOH　using　11-mercaptoundecanoic　acid　(MUA).　The　antibody　was　covalently　bound　on　the　work　area　to　form　a　label-free　immunosensor.　The　constructed　immunosensor　shows　high　sensitivity　with　a　good　response　in　the　range　of　low　concentrations　from　0.01　to　100　ng　mL-1,　low　detection　limit　(5.0　pg　mL-1),　high　selectivity　compared　with　some　possible　interference,　and　can　be　applied　in　a　bovine　serum　solution　without　the　need　of　sample　labeling　and　pretreatment.　Moreover,　the　immunosensor　is　mechanically　flexible　with　minimal　change　in　signal　output　after　bending　at　different　angles.　It　shows　an　easy　and　green　electrode　preparation　method　that　combines　3D　porous　structures　of　graphene,　uniform　immobilization　of　Au　NPs,　binder-free,　easy　covalent　binding　of　an　antibody,　and　good　mechanical　properties.　Hence,　the　present　method　has　great　potential　for　applications　involving　electrochemical　biosensors.　©　The　Royal　Society　of　Chemistry.