Abstract: This study presents a theoretical relation to predict the folding angle versus the time during the folding process in the thin walled square columns. Using the theoretical relation, diagram of the instantaneous folding force versus the time is obtained. Then, some experimental tests were performed on the aluminum square columns with the different strain rates. Comparison of the folding results shows that the increasing in the loading rate causes the increasing in the absorbed energy. Finally, the theoretical and experimental diagrams of the instantaneous folding force versus the time in the square column were compared that shows a good correlation.