Introduction and purpose: Reaching movement is one of the common task for assessing learning mechanism and is daily task in human life, improvement in postural stability can influence the function of this task. In this term, the aim of current study was to compare constant (simple reaction time) and variable random practice (choice reaction time) on the improvement of anticipatory postural adjustment during reaching task in healthy people. Methodology: Sixteen right handed women with the mean age of (27.18±3.18) participated in this study. For measuring magnitude of anticipatory postural control, centre of pressure displacement and centre of pressure velocity were evaluated by using force plate before reaching movement. Results: The results of mixed variance analysis in significant level of p<0.05 showed that random variable practice increased cop displacement and velocity before reaching task, but this increase wasn’t significant in acquisition and retention tests. Discussion and Conclusion: Therefore according to the results of this study, random variable practice improved anticipatory postural adjustment. Based on these results, effect of this practice on anticipatory postural control can be considered in rehabilitation programs.