Disclosed is a method for allocating data and pilots, a transmitting method and device, a receiving method and device in an OFDMA system. A terminal partitions subcarrier groups and symbols from an uplink channel based on a basic pilot pattern generated by a specific reference, receives at least one subchannel based on the partitioned subcarrier groups and symbols, hops the subcarrier groups caused by the subchannel according to hopping patterns, allocates data, and differently positions the pilots per subcarrier group based on the basic pilot pattern. Accordingly, the probability of pilot collision between adjacent cells is reduced, and accuracy of channel estimation is increased through boosting the pilot subcarrier power.