The subthalamic nucleus (STN) has been adopted as a commonly used surgical target in deep brain stimulation (DBS) procedures for the treatment of Parkinson's disease. Many techniques have been developed to facilitate STN DBS targeting, and consequently to improve the surgical outcome. In this work, we conducted a retrospective study on 10 patients who were treated with bilateral STN DBS to assess the target localization accuracy and precision of six methods in STN DBS surgery. A visualization and navigation system integrated with normalized functional and anatomical information was employed to perform the targeting procedures. Actual surgical target location determined by an experienced neurosurgeon with pre-operative image-guided surgical target/trajectory planning and intra-operative electrophysiological exploration and confirmation was considered as the "gold standard" in this evaluation and was compared with those localized using each of the six targeting methods. The mean distance between the actual surgical targets and those planned was 3.0 +/- 1.3 mm, 3.2 +/- 1.1 mm, 2.9 +/- 1.1 mm, 2.7 +/- 1.2 mm, 2.5 +/- 1.0 mm, and 1.7 +/- 0.8 mm for targeting approaches based on T2-weighted magnetic resonance image (MRI), brain atlas, T1 and T2 maps, electrophysiological database, collection of final surgical targets of previous patients, and the combination of these functional and anatomical data respectively. The results demonstrated that the use of functional data along with anatomical data provides reliable and accurate target position for STN DBS.