Novelty luminous carbonized polymer dots (CPDs) were synthesized by rapid and facile hydrothermal carbonization of sodium alginate (SA) and o-phenylenediamine (PDA). The SA-oPDA CPDs reveal a large Stokes shift up to 110 nm under the excitation wavelength at 352 nm and emission wavelength at 462 nm. The synthetic CPDs exhibited bright blue fluorescence with a fluorescence quantum yield of 16.9% and excellent photostability and excitation wavelength independence. Just for the characteristics of the alginate polymerization chain, the SA-oPDA CPDs also demonstrated the practical feasibility of establishing the fluorescent films by self-assembled chitosan polyelectrolyte molecular with electrostatic adsorption. Thus, it has great potential application in light-emitting devices. Meanwhile, the SA-oPDA CPDs were found to have extraordinary amphoteric charge adjustability by pH value. With the change of solution environment from acidic to alkaline, the position of the fluorescence emission peak changed from 465 to 425 nm, and the surface charge of the carbon point changed from positive charge to negative charge. The structure and morphology characterization showed that during the high-temperature carbonization process, the polymer is carbonized to form a luminescent carbon core and contains hydroxyl, amine, and carboxyl on the surface of CPDs. Due to the active protonation/deprotonation of amino or carboxyl groups, the CPD solution exhibits luminescence tunability with pH alterations. The SA-oPDA CPDs exhibited an amphoteric nature with the isoelectric point between pH of 6 and 7, respectively. After the CPDs were combined with lead ions in the solution environment at pH 6.80, the fluorescence emitted by the solution changed from blue to blue-green, which could realize an obvious visual response to a certain concentration of lead ions. The experimental results also showed that the reduced drug, especially quercetin(Que), had a significant quenching effect on the fluorescence signal of CPDs. The degree of fluorescence quenching had a good linear relationship with the concentration of quercetin in the range of 7.9×10-6~7.7×10-5 mol·L-1. The equation was I0/I=0.878 8+1.689 7×10-6cQue, correlation coefficient r2=0.974 8, and the LOD of detection was 1.7×10-6 mol·L-1.