Augmented feedback is information that guidance performance to direction correct response and has critical role in motor skill learning. The purpose of this study was to examine the effect of knowledge of results, after good and poor trials on learning and error estimation capability in children.32 elementary students (Mean age 10/4, SD ± 0/9) that all novice and no experience in dart skill participated in this research and randomly divided in two groups (good and poor feedback groups). Participants’ in acquisition phase exercise dart skill at 10 blacks (6-trial) and received knowledge of resulting feedback on 3 attempts in each block, also in all their trials on the acquisition and retention had error estimation. Multiplex Analysis of variance test (2*2) with repeated measures, independent t test and Multiple Analysis of variance test used to data analysis (α=0.05). There were significant difference between two groups in performance and error estimation in practice phase (p=0/001). Also, the good feedback group showed learning and error detection capability advantages on a delayed retention test (p=0/001). These results demonstrated that learning and error detection capability are facilitated if feedback is presented after good rather than poor trials.