The invention relates to a preparation method for heavy metal chelating agents of heat-sensitive ternary polymer molecule brushes. The preparation method is characterized by including the steps: dissolving 5-10 parts of heat-sensitive ternary polymer molecule brushes in 10-50 parts of water; mixing for 1-10 hours at the temperature ranging from 20 DEG C to 30 DEG C to obtain micellar solution of the heavy metal chelating agents of the heat-sensitive ternary polymer molecule brushes. The heat-sensitive ternary polymer molecule brushes comprise polymer side chains with three different functions, synergistic effect can be achieved when the molecule brushes capture heavy metal ions, and efficient capturing and rapid deposition functions are achieved. When heating temperature is higher than temperature of critical solution, millimeter-level aggregates are completely changed into hydrophobicity and rapidly deposited, and low-concentration heavy metal ions can be rapidly separated.