Randomized response with partial hiding is a privacy preservation algorithm based on association rule mining. For the insufficient that the exponential time complexity of the algorithm in the reconstruction of frequent item set support reduces the execution efficiency of the algorithm, the divide and conquer strategy and the set operations are used to improve the algorithm, and the exponential computation in the reconstruction is eliminated. The improved algorithm can reduce the time complexity and promote the efficiency effectively. Experiments and analysis indicate the effectiveness of the improved algorithm.