The present invention relates to a method and apparatus for an adaptive barring control for a Mobile Originating Short Message Service (MO-SMS). In one aspect of the present invention, a method for controlling an adaptive access class barring in a wireless access system, the method is performed by an enhanced Node-B (eNB) and comprises steps of estimating a SMS load, a MMTEL video load, and a MMTEL voice load on a cell of the eNB; generating a congestion level based on the MMTEL video load and the MMTEL voice load; determining an indication bit by comparing the SMS load with threshold values for the congestion level; and broadcasting an system information block (SIB) message including the indication bit. In this case, the indication bit indicates an open barring, a LessCongested or a MoreCongested to support the adaptive barring control.