Some foggy tone anomalies of grey-white and light-brown are always seen on the remote sensing imageries in some oil fields of Eastern China. The ground spectral test of vegetation and soil, and, the chemical inspection of soil. gas discovered that the spectra of vegetation and soil were different inside and outside the tons anomalies, and in which some hydrocarbon anomalies existed. Thus, the author supposed the tone anomalies might be related to the slightseepage of oil and gas. Through the digital processing of the imageries, such as contrast enhancement, regularizational alternation both of spectral and time variations etc, the tone anomalies on the imageries showed more clearly, and coincided with the known oil-gas structures very well.