The invention discloses a polyurethane associative thickener with double stimulus response and a preparation method thereof. The preparation method is characterized in that under the nitrogen gas protection, 4-hydroxyazobenzene methanol and halogenated alkyl ferrocene are dissolved; an acid binding agent is added; after the complete reaction, filtering is performed when the materials are hot; filtering liquid is collected; when the filtering liquid is cooled to room temperature, the filtering liquid is poured into saturated salt solution to obtain yellow precipitates; filtering is performed; the precipitates are washed; recrystallization is performed to obtain an end capping agent; under the nitrogen gas protection, a polyethylene glycol and methylbenzene mixture is subjected to temperature rise and water removal; after the solution is cooled, a catalyst and diisocyanate are added; temperature rise reaction is performed to obtain a methylbenzene solution of polyurethane prepolymers; the end capping agent is added; the temperature is raised to 70 to 100 DEG C for continuous reaction and end capping. The polyurethane associative thickener can effectively improve the viscosity of thewater solution in lower consumption; after ultraviolet light irradiation, the solution viscosity can be greatly reduced; after the oxidation, the solution viscosity can be greatly reduced; meanwhile,after the illumination and oxidation, the solution viscosity is greatly reduced.