This　study　presents　a　colorimetric　sensor　for　cancer　screening　utilizing　the　bifunctional　enzyme　activity　of　NiCo　Prussian　blue　analogue　(PBA),　a　PBA　material.　By　introducing　oxygen　vacancies　and　employing　a　dual-metal　doping　strategy,　NiCo　PBA　overcomes　the　limitations　in　catalytic　activity　observed　in　single-metal-doped　materials　(such　as　Ni　PBA　and　Co　PBA),　significantly　enhancing　both　peroxidase-like　(POD)　and　catalase-like　(CAT)　activities.　Compared　to　single-metal-doped　Ni　PBA　and　Co　PBA,　NiCo　PBA　exhibited　a　30.08-fold　increase　in　POD　activity　and　a　4.83-fold　increase　in　CAT　activity,　demonstrating　higher　sensitivity　in　carcinoembryonic　antigen　(CEA)　detection.　By　integrating　NiCo　PBA　with　a　cascade　catalytic　reaction　principle,　we　developed　a　highly　efficient　and　sensitive　CEA　detection　method.　NiCo　PBA　was　utilized　as　a　catalytic　material　in　this　method.　Under　the　action　of　glucose　oxidase,　the　decomposition　of　hydrogen　peroxide　was　catalyzed　by　NiCo　PBA,　and　oxygen　was　generated.　Furthermore,　a　blue　flocculent　substance　was　produced　when　NiCo　PBA　was　reacted　with　a　chromogenic　substrate.　Through　mutual　verification　by　these　two　methods,　the　quantitative　determination　of　CEA　in　serum　samples　was　achieved.　The　experimental　results　demonstrated　that　the　POD-like　activity　detection　range　was　0.2-50　ng　mL-1,　with　a　limit　of　detection　(LOD)　of　0.061　ng　mL-1,　while　the　CAT-like　activity　detection　range　was　0.1-20　ng　mL-1,　with　an　LOD　of　0.028　ng　mL-1.　The　sensitivity　of　this　method　was　substantially　increased　compared　to　monometallic　materials.　Furthermore,　this　strategy　possesses　good　scalability　and　can　be　adapted　for　the　detection　of　various　analytes　by　replacing　different　recognition　units,　providing　an　efficient　detection　platform　for　early　cancer　screening.　©　2025　American　Chemical　Society.