Disclosed is a method for controlling a reverse data rate by a mobile station in a mobile communication system supporting high-rate packet data transmission. The method includes receiving average loading information (FRAB) from a particular base station when the mobile station attempts an initial access to the base station; setting the received average loading information as average loading information for the base station; and upon receiving reverse activity information (RAB) from the base station, controlling a rate of reverse data using the received reverse activity information and the set average loading information.