A novel electrogenerated chemiluminescence (ECL) aptasensor for highly sensitive detection of thrombin was developed on the basis of poly(pyrrole-co-pyrrole propylic acid) nanoparticles loaded with aptamer and ruthenium complex. Thrombin binding aptamers served as the molecular recognition elements and ruthenium bis(2,2′-bipyridine) (2,2′-bipyridine-4,4′-dicarboxylic acid)-ethylenediamine (Ru1) was used as an ECL signal complex. Novel electroactive polymers poly(pyrrole-co-pyrrole propylic acid) nanoparticles (Ppy-pa NPs) were synthesized by a simple alcohol-assisted microemulsion polymerization. Ru1-Ppy-pa NPs were synthesized by covalently coupling Ru1 with the Ppy-pa NPs. Ppy-pa NPs and Ru1-Ppy-pa NPs were characterized using a fourier transform infrared spectrometer, super-conducting fourier digital NMR spectrometer, and transmission electron microscope. One ECL chemical sensor fabricated by immobilizing the Ru1-Ppy-pa NPs on PIGE was developed for the determination of TprA with a high sensitivity and stability. The ECL aptasensor was fabricated by covalently coupling the thrombin binding aptamer-I (TBA-I) onto the surface of the paraffin-impregnated graphite electrode, which had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations, for capturing thrombin onto the electrode and then the TBA-II labeled with Ru1-Ppy-pa NPs was bound with epitope of thrombin. The ECL aptasensor showed an extremely low detection limit of 3.0×l0?16 mol/L for thrombin and a good selectivity. This work demonstrated that using Ppy-pa NPs as a carrier of ruthenium complex and molecular recognition element was a promising approach for the fabrication of ECL biosensor with high sensitivity. A novel electrogenerated chemiluminescence (ECL) aptasensor for highly sensitive detection of thrombin was developed on the basis of poly (pyrrole-co-pyrrole propylic acid) nanoparticles loaded with aptamer and ruthenium complex. Thrombin binding aptamers served as the molecular recognition elements and ruthenium bis (2,2’-bipyridine-4,4’-dicarboxylic acid) -ethylenediamine (Ru1) was used as an ECL signal complex. Novel electroactive polymers poly (pyrrole-co-pyrrole propylic acid) Ppy-pa NPs and Ru1-Ppy-pa NPs were synthesized by a simple alcohol-assisted microemulsion polymerization. Ru1-Ppy-pa NPs were synthesized by covalently coupling Ru1 with the Ppy-pa NPs. using a fourier transform infrared spectrometer, super-conducting fourier digital NMR spectrometer, and transmission electron microscope. One ECL chemical sensor fabricated by immobilizing the Ru1-Ppy-pa NPs on PIGE was developed for the determination of TprA w ith a high sensitivity and stability. The ECL aptasensor was fabricated by covalently coupling the thrombin binding aptamer-I (TBA-I) onto the surface of the paraffin-impregnated graphite electrode, which had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations for capturing thrombin onto the electrode and then the TBA-II labeled with Ru1-Ppy-pa NPs was bound with an epitope of thrombin. The ECL aptasensor showed an extremely low detection limit of 3.0 × 10 16 mol / L This work demonstrates that using Ppy-pa NPs as a carrier of ruthenium complex and molecular recognition element was a promising approach for the fabrication of ECL biosensor with high sensitivity.