Abstract: For accomplishing acoustic location in WSN, a range-free acoustic localization algorithm based on perpendicular bisector partition is presented, taking account of reducing computation complexity and weaken the noise disturbing. With adopting a range-free perpendicular bisector partition, this method can ascertain the location block of source and its time complexity is O(N²) which is much lower than traditional methods' O(N³). Based on in-depth research of noise, the concept of sensitive region of noise is proposed. After the improvement, measurement error has been dwindled over 37%. Experiment results show that the method not only executes perfectly in WSN but also has a good locating accuracy.