This paper addresses organic matter content, sition of humus, content of O-containing functional group and infrared spectrum characteristics of humus in salt affected soil under different age of amelioration at the Quzhou Experimental Area in Hebei Province. The results of the experiment show that with increasing age of soil amelioration and improving fertilization and cultivation levels. The quantity and quality of soil organic matter in the salt affected soil improved steadily from the first generation to the second generation and the third generation of experimental area successively which is demonstrated by the increases in content of total humus, HA/FA ratio, and content of functional group, and decrease in E₄₆₅/E₆₆₅ rate. There are indications in the results of the infrared spectrum analysis that the soil humus was a complicated system of multi functional groups. The type of HA had changed from Rp to B type from saline land to the first generation of experimental area, indicating that the soil humns was developing forwards complicated structure and diversified function. The content and quality of the organic matter in the ameliorted salt affected soil have approached to the level of the local non-salt affected soil-bright meadow soil.