Heilongjing province and Hulunbeier League, located at 42°34′N and with an area of about 710 000 sq. km, is the northern most province of China. Up to the end of ninteenthcentury, the region was called the "great northern wilderness". In less than 100 years, it has been rapidly turned into the "great northern granary". It has now 8.73 million hectares of cropland, occupying about one twelfth of the total cropland, and producing about one sixth of the total commercial grains in China. There are still about 7.41 million hectares o?arable virgin land which will enhance the development of this commercial grain base to an even higher level.The present paper consists chiefly of five parts.In the first part, natural conditions of the Heilongjiang province are briefly introduced. In general, the temperature, moisture and soil conditions are favorable for agriculture, although there are also some unfavorable natural conditions, such as low temperature, spring drought, summer flood, soil erosion and salinization in different areas and in varying intensities.In the second part, the history of agricultural reclamation is briefly reviewed. Three periods are dentified: (1) Up to 1897 A. D., there were about 5300 hectares of cropland. (2) From 1897 up to 1949 A. D., agricultural reclamation by small farmers developed very quickly. In about fifty years, the northern part of the Songhua-Nen Jiang plain and the whole Mudan Jiang valley were already well developed. In 1949, croplands of Heilongjiang province totalled about 5.7 million hectares. (3) After 1949 A. D., the agricultural reclamation by state farms and people’s commune has reached a new high level. The newly reclaimed areas have been mostly located in the Three River plain and in the piedmonts of the Great and Small Xing-an Ranges.In the third part, the present croplands are analyzed and assessed. Most of them are favorable for agriculture. But, as three-fourths of them are located at the gently, rolling slopes, soil erosion has been rather severe. According to an estimate, one half of the total cropland is subjected to erosion, and about one fourth of which is very severe. The land has been gradually degraded. Again, the producing capability of the cropland has not yet been fully developed, so far, yield per area is rather low.In the fourth part, arable virgin lands are evaluated. The total area is about 6.7 million hectares. According to their capability to be used productively, they may be classified into four categories. They may also be grouped into four land types: gentle slope, flat ground, meadow and marsh.In the last part, chief measures for increasing commercial grain production are introduced.