The invention discloses a heavy environmentally-friendly rubber oil and a preparation method thereof. The method comprises the following steps: extracting inferior cycloalkyl heavy wax oil in a propane deasphalting extraction tower with propane obtain a refined liquid at the top of the propane deasphalting extraction tower, and recovering a solvent to obtain refined heavy wax oil; and 2, carrying out solvent refining of the refined heavy wax oil in an extracting tower I to obtain a primary refined liquid at the top of the extracting tower I and a primary extract liquid at the bottom of the extracting tower I, and recovering the solvent of the primary extract liquid to obtain primary extract oil; and 3, carrying out solvent refining of the primary refined liquid in an extracting tower II to obtain a secondary refined liquid at the top of the extracting tower II and a secondary extract liquid at the bottom of the extracting tower II, recovering the solvent of the secondary refined liquid to obtain secondary refined oil, and recovering the solvent of the secondary extract liquid to obtain the heavy environmentally-friendly rubber oil. The method utilizing the inferior cycloalkyl heavy wax oil to prepare the environmentally-friendly rubber oil widens the raw material resource of the environmentally-friendly rubber oil, satisfies the market demands at home and abroad, and also greatly improves the added values of the inferior cycloalkyl heavy wax oil.