The present invention provides an amphiphilic polymer, a water-dispersible aldehyde functionalized fluorescent nanometer micelles, and preparation methods of the amphiphilic polymer and the water-dispersible aldehyde functionalized fluorescent nanometer micelles, wherein the amphipathic compound is a hybrid structure polymer comprising a hydrophobic hyperbranched conjugated polymer and a hydrophilic linear polyether, the hydrophilic linear polyether is linked to the terminal of the hyperbranched conjugated polymer, and the terminal of the hyperbranched conjugated polymer is further linked to an aldehyde functional group. According to the present invention, the small size nanosphere is obtained based on the self-assembly of the amphiphilic polymer, wherein the core is the hydrophobic hyperbranched conjugated polymer with fluorescence property, the shell is the hydrophilic linear polyether, and the core is provided with the aldehyde functional group; the fluorescent nanometer micelle aqueous solution emits bright green fluorescence under ultraviolet light irradiation, the maximum emission wavelength is about 500 nm, and the fluorescent nanometer micelles have good application prospects in the field of functionalized fluorescent nanometer probes; and by further regulating the amphiphilic polymer and the self-assembly condition, the nanometer micelles with the nanoparticle size of less than 100 nm can be obtained so as to provide more advantages.