Abstract: The horizontal structure is examined of the outgoing longwave radiation (OLR) anomalies in the tropics on the quasi-biennial period time scale during 1974-1986. The techniques of the band pass filter and multiple statistics are used. The primary results show that : (1) the band of high relative variance is found stretching from Indonesia to the equatorial Atlantic coast of Brazil along the equatorial Pacific; (2) The horizontal structure in the 15°N-15°S zone takes up the pattern of zonal dipole, which coincides with the planetary wavenumber 2 in the tropics; (3) the dipole in OLR anomalies between the maritime conth and the equatorial central Pacific is related to the equatorial QBO; (4) there exists the quasi-stationary wave oscillation for an area from East Africa to the equatorial central Pacific (30°E-150°W); and (5) zonal phase propagation is westward for an area from the equatorial eastern Pacific to the equatorial Atlantic coast of Brazil (140-40°W).