Methods　derived　from　immunoassays　and　aptasensors　have　been　established　for　monitoring　of　carcinoembryonic　antigen　(CEA)　in　biological　fluids,　but　most　involved　complex　procedure　and　various　reactions.　We　designed　an　uncomplicated　and　convenient　electrochemical　aptasensing　platform　for　the　quantitative　monitoring　of　CEA　on　multifunctionalized　magnetic　beads　with　a　handheld　pH　meter　as　the　read-out.　Initially,　CEA-specific　aptamers　were　covalently　conjugated　to　magnetic　beads,　and　then　hybridized　with　glucose　oxidase-labeled　complementary　strands　to　construct　multifunctional　nanoprobes.　After　addition　of　target　CEA,　the　analyte　interacts　with　the　corresponding　aptamer　and　then　release　the　complementary　strand.　After　magnetic　separation,　the　released　glucose　oxidase-labeled　complementary　strands　hydrolysed　glucose,　thereby　leading　to　a　change　in　pH　of　the　detection　solution,　which　was　quantitatively　monitored　on　a　hand-held　pH　meter.　Under　the　optimum　conditions,　the　aptasensor　based　on　pH　meter　exhibited　well　responses　relative　to　CEA　concentrations　inside　the　dynamic　range　between　0.01　and　100　ng　mL(-1)　and　detection　limit　at　least　9.3　pg　mL(-1).　Good　duplicability,　high　specificity　and　ability　for　long-term　stable　storage　are　obtained　for　the　as-prepared　aptasensors.　Additionally,　human　serum　specimens　were　determined　through　pH-meter-based　aptasensors,　and　the　results　closely　matched　the　commercial　enzyme-linked　immunosorbent　assay　(ELISA)　of　human　CEA.