This paper reviews results of the authors' studies about the relationship of intraseasonal variations between atmosphere and ocean over the South China Sea and tropical western North Pacific during the recent several years. The review compares the difference of the relationship between the 10-20-day and 30-60-day time scale intraseasonal variations and that between winter and summer. It is found that the 10-20-day intraseasonal oscillations (ISOs) account for a larger part of the intraseasonal variance in the atmosphere compared to the 30-60-day ISOs, whereas the 30-60-day ISOs explain a larger part of the intraseasonal variance in sea surface temperature (SST) than the 10-20-day ISOs except over the low-latitude western North Pacific, where the contribution of 10-20-day ISOs is comparable to or slightly larger than that of 30-60-day ISOs. In the boreal summer, the 10-20-day ISOs display a distribution along the southwest-northeast direction and northwest-westward propagation from the equatorial western Pacific, whereas the 30-60-day ISOs display a west-east distribution and northward propagation. In the boreal winter, the two ISOs display a similar distribution featuring a southwest-northeast orientation. The ISOs display a unique southward propagation over the South China Sea during boreal winter and a close association with the intraseasonal variation of the East Asian winter monsoon. Over the South China Sea-Philippine Sea, the 10-20-day ISOs intensify during the El Niño developing summers, whereas the 30-60-day ISOs tend to enhance during the La Niña decaying summers. Further analysis reveals that the intraseasonal variations, particularly on the 10-20-day time scale, around the inter-tropical convergence zone over the tropical western North Pacific have a prominent feedback on seasonal mean SST anomalies in boreal summer.