Abstract: Based on the analysis data of organic matters in black soil during the second national soil survey in the 1980s and those in the current land quality geochemical survey, the MapGIS spatial analysis is used to quantitatively study the spatial variation of organic matter content in the black land core area of Northeast China. The results show that the content of soil organic matters decreases from 41.16×10^-3 to 37.68×10^-3 in recent 30 years, with the organic matter loss rate of 8.45%. In 1980s, the areas with soil organic matter content of 35×10^-3-45×10^-3 account for 73.93% of the total study area, while the areas with soil organic matter content of 30×10^-3-40×10^-3 make up 70.24% currently. Of the land area, 82.1% shows different degrees of reduction in organic matter, while only 17.9% shows an increasing trend. The black land is dominated by mild and slight loss of soil organic matter, except for local areas with moderate and severe loss degree, which provides scientific basis for soil organic matter loss control in black land region.