Using biomass residue as a source of carbon precursors, a pyrolysis method was used to prepare biomass-derived luminescent Carbon Quantum Dots (CQDs). The prepared CQDs exhibited excellent fluorescence and luminescence properties and fluorescence behaviors of CQDs acquired at different pyrolysis temperatures varied. Importantly, the CQDs showed superior surface activity and the styrene-in-water Pickering emulsion prepared using the CQDs as nano-sized surfactant was highly stable: the higher the pyrolysis temperature the better the stability of the emulsion. In addition, there was no stratification found in the emulsion which was stabilized by the CQD500 (CQDs prepared at 500 °C) after holding for 72 hours. This research provided an approach for preparing the surfactants of nano-sized particles in large scale. The CQDs prepared using the proposed methods are expected to have a high number of potential applications.