Combining the advantages of electrochemistry,chemiluminescence and immunoassay,electrochemiluminescence（ECL）immunoassay possesses features of high specificity,high sensitivity,as well as low background signal,which have been broadly used in early prognosis as well as clinical detection of diseases.But,it is difficult to achieve the trace detection of disease markers relying on the ECL suppression of targets.To meet this pursuit,the construction of a quenched ECL biosensor based on a high-efficiency quencher is the detection of low abundance of disease markers provides a new research direction.This thesis mainly uses carbon materials as ECL emitters.Luminescence materials（carbon materials）,based on the energy transfer between ceria@polydopamine（CeO2@PDA）composites,copper sulfide@cobalt disulfide double shelled nanoboxes（Cu S@CoS2 DSNBs）,and carboxyl cobalt disulfide nanoboxes（carboxyl CoS2 NBs）,design high-efficiency quenching sensing strategies,and explore the quenching mechanism.A series of ECL immunoassays are designed and used for sensitive analysis of disease markers.The main research contents of the thesis are as follows:（1）Based on the relationship between 1-pyrene butyric acid（Py-COOH,sodium salt）modified CNNS（m-CNNS）and CeO2@PDA composites quenching constructs sandwich type electrochemiluminescence immunosensor.For the detection of brain natriuretic peptide（BNP）,m-CNNS is used to connect the capture antibody.CeO2@PDA is used as a label to connect the BNP detection antibody.After specific recognition between antigen and antibody,the ECL signal of m-CNNS can be quenched.Under the best experimental conditions,the immunosensor can achieve sensitive detection of BNP in the range of 0.5 pg/mL-100 ng/mL,with a detection limit of 0.1 pg/mL.This quenching construction strategy will have potential applications in the early detection of very low concentrations of disease markers.（2）A sandwich-type ECL immunosensor was prepared based on the quenching effect of Cu S@CoS2 DSNBs on gold nanoparticles functionalized carbon nitride（Au@C3N4）composites electrochemiluminescence.The sensor was used for quantitative detection ofβ-amyloid1-42 oligomers.The prepared Au@C3N4composites could could also worked as the substrate for fixing the primary antibody（Ab1）through the Au-N Bond,in addition to supplying the excellent ECL signal sources.Using K2S2O8 as the coreactant,electrochemiluminescence behaviour of Au@C3N4could be observed.Silver nanoparticle modified Cu S@CoS2 double shelled nanoboxes（Cu S@CoS2DSNBs@Ag NPs）as a secondary antibody marker immobilized the Aβdetection antibody.Based on the energy transfer between Au@C3N4（donor）and Cu S@CoS2 DSNBs@Ag NPs（acceptor）,we constructed a dual-quenching type ECL immunosensor and used to detect Aβ.Under optimal experimental conditions,the sensor detects Aβin the range of 0.5 pg/mL-20 ng/mL and the detection limit was 0.0038 pg/mL.The sensor also provides important references for highly sensitive detection of other disease markers.（3）An immunosensor based on carboxyl CoS2 NBs quenching graphitic carbon nitride coupled bismuth molybdenum oxide（g-C3N4/Bi2Mo O6）electrohemiluminescence was constructed,and then it was used for sensitive detection of alpha fetoprotein（AFP）.Emloying K2S2O8,ECL behaviour of g-C3N4/Bi2Mo O6 could be observed.So that,energy transfer between g-C3N4/Bi2Mo O6 and CoS2 NBs can occur,triggering ECL quenching effects.Under optimal experimental conditions,the sensor detects AFP in the range of 0.5 pg/mL-20 ng/mL and the detection limit was 0.04 pg/mL.As emerging electrochemiluminescence（ECL）emitters,graphitic carbon nitride（g-C3N4）composites not just possess the advantages of pristine g-C3N4 with good biocompatibility,despite improve its dispersion as well as ECL efficiency.That’s why,they have presently become a rising attention in ECL.We summarized the recent progress of various g-C3N4composites ECL systems as well as associated applications in biosensors.We highlight the enhanced ECL performances of different g-C3N4 composites,such as metal nanoparticles/g-C3N4 composites,metal nanoparticles/C3N4 composites,metal oxide/g-C3N4composites and other material/g-C3N4 composites.Lastly,this thesis ends through perspectives in searching novel and effective g-C3N4 composites/capable energy acceptors or C3N4 composites/capable energy acceptors ECL systems and in assembling sensitive ECL biosensors.