This study focuses on the improvement of square jacketing technique in effective restrengthening of existing RC building column. Square jacketing technique can’t effectively provide lateral confinement due to stress concentration and subsequent cracking at the corners. In order to overcome this problem, two different approaches are taken into account; i.e. (a) strengthen all the corners, and (b) reducing stress concentrations at corners. Three types of square jacketing techniques under these two approaches are considered in this study. Test results and crack pattern shows that, both approaches are effective to overcome the stress concentration problem of square jacketing. However, the first approach is practically more suitable than the second one.