Abstract: This paper selects the disciplines of Library Science & Information Science and Psychology under the category of Social Sciences and the disciplines of Biochemistry & Molecular Biology and Mechanical Engineering under the category of Natural Science as sample disciplines. The aim is to use Mendeley readership altmetrics to reveal the audience and scope of influence of publications from China and USA. Major findings are: (1) According to Mendeley readership altmetric indicator, the proportion of international papers read in China is higher than that in the United States, but the intensity of reading is lower than that in the United States.(2) Mendeley readership of China is dominated by students (about 60%), among them, the doctoral student reader is in the leading position (about 30%). However, there are disciplines differences in the distribution of reader identity. (3) The subject distribution of Mendeley readers of Science and Engineering papers in China and the United States is consistent, while that of Social Science papers is different.(4) The international papers of China in four disciplines are mainly read by readers of other countries, and the visibility of readers from China is low. In Mechanical Engineering, Chinese and American academic papers have the highest proportion of Japanese readers, and Chinese papers have attracted more readers from developing countries such as India and Brazil, while American papers have attracted more readers from developed countries such as Britain and Korea. These conclusions indicate that the Mendeley readership altmetric indicator is helpful to identify the use of academic papers more thoroughly, track and compare the influential directions of academic papers in different disciplines and countries, and provide reference for a more comprehensive understanding of the communication and impact of academic papers.

Key words: Altmetrics, Mendeley, Scientific evaluation, Impact, Mendeley readership altmetric indicator