Method for Preparing Modified Conjugated Diene-Based Polymer

A method for preparing a modified conjugated diene-based polymer, the method comprising:

• polymerizing a conjugated diene-based monomer in the presence of a catalyst composition comprising a neodymium compound, a first alkylating agent, a second alkylating agent and a halide in a hydrocarbon solvent to prepare an active polymer;
• and
• reacting or coupling the active polymer with a modifier,
• wherein a molar ratio of the neodymium compound to the second alkylating agent is 1:20 to 1:35, and
• the polymerization is performed at a temperature of 30 to 65° C.