The tracking of micro sized colloidal particles which are optically trapped is an important method to gain information about the pair interaction potential between particles suspended in a liquid. To track the particles which are close to contact is difficult because the overlapping of the particle diffraction patterns causes systematic errors in the position detection. Recently, a template based the particle finding algorithm was reported and verified experimentally. Here, we perform simulations in order to determine the precision of that algorithm, as one cannot know the real positions of the particles in the experiment. We generate the particle images by using fitted curve to experimental. data. As a result, we found that the proposed algorithm predicts correctly the positions with an isolated reference particle and it has the maximum error about 0.065 pixels (5.5nm) in the particle images.