To exploit more effective organic binder for iron ore pellet, it is necessary for us to find the systematic theory of the relationship between organic binder′s molecular structure and its properties.In this paper,the molecular structure mould(X—P—K) of organic binder is proposed. The electronegativity of polar group COO - and hydrophilic group -O - are calculated as an example, so the priliminary selecting criterion of polar group and hydrophilic group are defined. The authors has analysed the relationship between organic chain structure and its properties,and considered that the annular netty structure organic chain is better. Based on the molecular structure mould and selecting criterion, a new kind of organic binder S 1 has been synthesized.The effect of the pelletizing experiment indicate that the properties of organic binder S 1 are effective, especially, the dry ball’s compression strength is up to 322.8 N per ball,dropping strength is 16.18 per meter,the green ball shook temperature is 820 ℃, which has solved the problem of baffle thermal stability existing in other organic binder used in pelletizing. [