The current analytical method on bi-directional shearing capacity of RC framed columns, the so called "over strength factor method", in the drafting "Design Code of RC structures", is carefully investigated. Limits of this method are presented and suggestions are put forward to modify it. On this basis, the simplified tri linear analytical method to determine bi directional shearing capacity is presented afterwards and the error of this method is given. Finally, the cases of design and check of the two methods are illustrated.