Submicron-sized Ag-polypyrrole/poly(styrene-co-methacrylic acid) (Ag-PPy/P(St-co-MAA)) composite particles were fabricated via a redox reaction between pyrrole and AgNO3 in the presence of P(St-co-MAA) soap-free latex. The products are characterized by transmission electron microscopy (TEM), electron diffraction spectra (EDS), Raman spectra, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results showed that Ag-PPy nanocomposites were in situ deposited onto the surface of P(St-co-MAA) latex particles tailored by carboxylic-acid groups. The nanocomposites of Ag-PPy distributed on the surface of polymer particles transformed from discretely dots to continuously coating as the reaction temperature increased from 15℃ to 60℃. Strawberry-like composite particles were obtained at the reaction temperature of 60℃. The TGA characterization confirmed that the Ag-PPy nanocomposites loading onto the P(St-co-MAA) particles were systematically controlled over a range of 6 wt% 42 wt% by changing the reaction temperatures. The fluorescence quenching effect of the Ag-PPy/P(St-co-MAA) composite particles was explored on Rhodamine B as a model molecule with the Stern-V lmer quenching constant KSV of 5.9 × 104 (g/mL)-1 . It is suggested that the fluorescence quenching effect is caused by the resonance energy transfer mechanism. Submicron-sized Ag-polypyrrole / poly (styrene-co-methacrylic acid) (Ag-PPy / P (St-co- MAA)) composite particles were fabricated via a redox reaction between pyrrole and AgNO3 in the presence of P co-MAA) soap-free latex. The products are characterized by transmission electron microscopy (TEM), electron diffraction spectra (EDS), Raman spectra, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) PPy nanocomposites were in situ deposited onto the surface of P (St-co-MAA) latex particles tailored by carboxylic-acid groups. The nanocomposites of Ag-PPy distributed on the surface of polymer particles transformed from discretely dots to continuously coating as the reaction The TGA characterization that the Ag-PPy nanocomposites loaded onto the P (St-co-MAA) particles were systematically controlled over a rang e of 6 wt% 42 wt% by changing the reaction temperatures. The fluorescence quenching effect of the Ag-PPy / P (St-co-MAA) composite particles was explored on Rhodamine B as a model molecule with the Stern-V lmer quenching constant KSV of 5.9 × 104 (g / mL) -1. It is suggested that the fluorescence quenching effect is caused by the resonance energy transfer mechanism.