Objective  In order to define the core journals of biology and medicine in our library and to establish distinctive library collection.Method  Through the library circulation file statistical analysis,we collected the data about the   reader’s   information desires,and further define the core journals by citation analysis.Result  Through the investigation and analysis,we found that the references refered by our postgraduates and researchers concentrated on 188 foreign professional journals and 69 chinese professional journals.So we could define that these 188 foreign periodicals and 69 chinese journals were the core journals of our library.Conclusion  The results of this investigation can be regarded as the basis of defining the direction of our library journal collection.