The aim of this study was examining the effect of knowledge of results presentation (after successful and unsuccessful trials), on learning and error detection capability in force-produce task. Sixty under graduated students (range age 21.6±4), participated in this study and in order to KR presentation, divided in three groups. One of the groups received KR after successful trials, the other groups after unsuccessful trials. The control groups did not receive any KR. All the participants throughout the trials in the acquisition and retention phases were error estimated. The task was to produce the 70℅ of maximum force of their right hands, by gripping a dynamometer. After data collection, the analysis conducted by using ANOVA repeated measurements for acquisition period, and one way ANOVA for retention test. In acquisition, results showed no significant differences between the first and second groups, on performance and error detection capability of force-produce task (P> 0.05). However in retention (no KR), there was significant differences between two groups (P&le0.05), means that the first group which received KR after successful trials was better than the second group as well as control. This pattern of results suggests that if people receive the KR after successful trials than unsuccessful, the better learning and error detection capability will occur.