The difference lies in the importance of subject matter, the innovation of research ideas, methods and conclusions, and the contribution of the paper. The specific differences are as follows:

1. Importance of theme: Excellent papers are more forward-looking and practical in topic selection, and can discuss and solve practical problems from a macro or national perspective. The second kind of papers are more confined to the in-depth exploration of a certain field or problem.

2. Innovation of research ideas, methods and conclusions: Excellent papers are highly innovative and independent in research ideas, methods and conclusions, and can propose new research methods or technologies. Second-class papers are slightly lacking in innovation.

3. Paper contribution: Excellent papers can make important contributions in theory and practice, and their research results or application values have high social and economic benefits. The contribution of second-class papers is slightly inferior.