Abstract: In this paper, We have made a preliminary study on the variation features for the Low -Frequency Oscillation.(LFO) in the tropical region. The results ave as follows;1. The activity areas for the 30-60 day oscillation of the OLR data are located in North Indian Ocean, subtropical and tropical Western Pacific Ocean. The integrated power spectra for the 30-60 day period range is large during the normal years,and small during the El Nino years.2. There exists large difference for LFO between summer and winter with its large inter annued variability being mainly confined to the equatorial region during winter and to the Indian Ocean and western pacific during summer.3. The meridional propagation of LFO over the western pacific and Indian Oceans is obvious and the zonal propagation of LFO over the equatorial region is mainly concentrated in northern summer.4. The intensity of filtered 30-60 day OLR field can reflect the "active" and "break" phases for the Indian Monsoon.