Abstract: In recent years, patent citations have increasingly been used to study the knowledge activities between technology fields, such as technology path research, technology convergence, and technology diffusion. But they haven't effectively distinguished applicant citations and examiner citations. Previous studies on the differences between applicant cit ations and examiner citations from, the technical field level have remained at a relatively low statistical level. In this paper, based on the distribution of technical categories, discrepancy between the technical categories themselves was introduced into the study to explore knowledge sources from the perspectives of the diversity of technical fields of applicants and examiners, respectively. The results showed that applicant citations covered more technical fields, whereas examiners were more focused on the fields that they were familiar with, and the diversity of applicant citations in most technical fields was higher than that of examiner citations. Further, it was found that there was a significant positive correlation between applicant citations and examiner citations in both aspects.