Novel cellulose nanomicelles self-assembled from amphiphilic cellulose-graft-poly(p-dioxanone) (MCC-graft-PPDO) copolymer were used to encapsulate and disperse hydrophobic fluorescent conjugated polymers (FCPs) in water for tumor cell imaging. Three different conjugated polymers were employed to demonstrate the versatility of the cellulose nanomicelles, resulting in highly fluorescent and stable polymeric nanoparticles with different emission wavelengths across the visible spectrum. Owing to the size effect of cellulose nanomicelles, the incorporated conjugated polymers present red-shifted emission to low-energy sites, and the fluorescence self-quenching of conjugated polymers at high concentration can be greatly inhibited. The in vitro studies using the liver cancer Hep3B cells and the breast cancer MAD-MB-231 cells indicate these amphiphilic cellulose/FCPs nanomicelles have negligible cytotoxicity even at high concentration of up to 100 mu g/mL. Moreover, the light-emitting micelles are successfully uptaken by the cancer cells and located at the cytoplasm of the cells, suggesting their great potential for tumor cell imaging and early detection of tumor cells.