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Asian dust storms, which can long-range transport to ocean, often occur during spring. The present of Asian dust aerosols over ocean makes some difficult for other studies, such as cloud detection, and also provide some advantages for ocean, such as adding nutrition to the ocean by dry or wet deposition. Therefore, it is important to study the dust aerosol and retrieve the properties of dust from satellite observations using mainly the thermal infrared radiance. In this paper, the thermal infrared radiance properties of dust aerosol over ocean are analyzed from MODIS and MTSAT2 observations and Streamer model simulations. By analyzing some line samples and a series of dust aerosol region, it shows that the dust aerosol brightness temperature at 12 mu m (BT12) is always greater than BT11 and BT8.5, and BT8.5 is general greater than BT11. The different between brightness temperature at 11 mu m and 12 mu m wavelengths (BTD11-12) increases with the dust intensity. Also, the BTD11-12 becomes positive when the atmospheric relative humidity is greater than 70%. The BTD11-12 increases gradually with the surface temperature while the effect of dust layer temperature on BTD11-12 is not evident. Those are caused by the transmission of the dust aerosol, which is different at the two thermal infrared channels. During daytime, dust infrared brightness temperature at mid-infrared bands should reduce those computed from the reflected solar radiance by dust. In general, BT3.7 is greater than BT11 for dust aerosol. Those results are helpful to monitor or retrieve dust aerosol physical properties over ocean from satellite.