The present invention particularly relates to a method and an apparatus for improving the efficiency of data transmission in a multi-user wireless transmission system. According to one embodiment of the present invention, the method, which is a transmission method of data in a multi-user wireless communication system, comprises the steps of: estimating channel states of each terminal through sounding or feedback information received from the terminals, and selecting terminals to which individual data are to be transmitted at the same time; determining a signal to noise ratio of the selected terminals, and calculating a precoding matrix; calculating a modulation and coding scheme (MCS) of each terminal and the number of symbols of data fields in accordance with the MCS of each terminal; dividing an area according to the number of terminals to which the data fields are to be simultaneously transmitted, if there are two or more selected terminals; and recalculating a reception signal to interference and noise ratio (SINR) for each area of each terminal, configuring a packet by resetting the MCS according to the recalculated SINR, and transmitting the configured packet.